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Han van Meegeren

Henricus Antonius "Han" van Meegeren (10 October 1889 – 30 December 1947) was a Dutch painter and portraitist, considered one of the most ingenious art forgers of the 20th century. Van Meegeren became a national hero after World War II when it was revealed that he had sold a forged painting to Reichsmarschall Hermann Göring during the Nazi occupation of the Netherlands.

Van Meegeren attempted to make a career as an artist, but art critics dismissed his work. He decided to prove his talent by forging paintings from the Dutch Golden Age. Leading experts of the time accepted his paintings as genuine 17th-century works, including Dr. Abraham Bredius.

During World War II, Göring purchased one of Meegeren's "Vermeers", which became one of his most prized possessions. Following the war, Van Meegeren was arrested on a charge of selling cultural property to the Nazis. Facing a possible death penalty, Van Meegeren confessed the painting was a forgery. He was convicted on 12 November 1947, and sentenced to one year in prison. However; he died on 30 December 1947 after two heart attacks. A biography in 1967 estimated that Van Meegeren duped buyers out of more than US$30 million; his victims included the government of the Netherlands.

Early years
Han (diminutive for Henri or Henricus) van Meegeren was born 10 October 1889, the third of five children of Augusta Louisa Henrietta Camps and Hendrikus Johannes van Meegeren, a French and history teacher at the Kweekschool (training college for schoolteachers) in the provincial city of Deventer.

While attending the Higher Burger School, Han met teacher and painter Bartus Korteling (1853–1930) who became his mentor. Korteling had been inspired by Johannes Vermeer and taught Van Meegeren Vermeer's techniques. Korteling had rejected the Impressionist movement and other modern trends as decadent, degenerate art, and his strong personal influence may have led van Meegeren to do likewise.

Van Meegeren's father did not share his son's love of art; he often forced Han to write a hundred times, "I know nothing, I am nothing, I am capable of nothing." Instead, Han's father compelled him to study architecture at the Delft University of Technology in 1907. He received drawing and painting lessons, as well. He easily passed his preliminary examinations but never took the Ingenieurs (final) examination because he did not want to become an architect. He nevertheless proved to be an apt architect and designed the clubhouse for his rowing club in Delft which still exists (see image).

In 1913, Van Meegeren gave up his architecture studies and concentrated on drawing and painting at the art school in The Hague. On 8 January 1913, he received the prestigious Gold Medal from the Technical University in Delft for his Study of the Interior of the Church of Saint Lawrence (Laurenskerk) in Rotterdam. The award was given every five years to an art student who created the best work, and was accompanied by a gold medal.

On 18 April 1912, Van Meegeren married fellow art student Anna de Voogt who was pregnant with their first child. The couple initially lived with Anna's grandmother in Rijswijk, and their son Jacques Henri Emil van Meegeren was born there on 26 August 1912.

Career as a legitimate painter
In 1914, Van Meegeren moved his family to Scheveningen and completed the diploma examination at the Royal Academy of Art in The Hague, which allowed him to teach. He took a position as the assistant to the Professor of Drawing and Art History. In March 1915, his daughter Pauline was born, later called Inez. To supplement his small salary of 75 guldens per month, Han sketched posters and painted pictures for Christmas cards, still-life, landscapes, and portraits for the commercial art trade. Many of these paintings are quite valuable today.

Van Meegeren's first exhibition was held from April to May 1917 at the Kunstzaal Pictura in the Hague. In December 1919, he was accepted as a member by the Haagse Kunstkring, an exclusive society of writers and painters who met weekly on the premises of the Ridderzaal. Although he had been accepted, he was ultimately denied the position of chairman. He painted the tame roe deer belonging to Princess Juliana. The painting, Hertje (The Fawn or The Deer), was completed in 1921, and became popular in the Netherlands. He undertook numerous journeys to Belgium, France, Italy, and England, and acquired a name for himself as a portraitist, earning commissions from English and American socialites who spent their winter vacations on the Côte d'Azur. His clients were impressed by his understanding of the 17th-century techniques of the Dutch masters. Throughout his life, Van Meegeren signed his own paintings with his own signature.

By all accounts, infidelity was responsible for the breakup of Van Meegeren's marriage to Anna de Voogt; the couple divorced on 19 July 1923. Anna moved to Paris, where Van Meegeren visited his children from time to time. He dedicated himself to portraiture and began producing forgeries to increase his income.

He married actress Johanna Theresia Oerlemans in Woerden in 1928, with whom he had been living for the past three years. Johanna's stage name was Jo van Walraven, and she had previously been married to art critic and journalist Dr. C H. de Boer (Carel de Boer). She brought their daughter Viola into the Van Meegeren household.

Rejection by the critics
Van Meegeren had become a well-known painter in the Netherlands with the success of Hertje (1921) and Straatzangers (1928). His first legitimate copies were painted in 1923, his Laughing Cavalier and Happy Smoker, both in the style of Frans Hals. By 1928, the similarity of Van Meegeren's paintings to those of the Old Masters began to draw the reproach of Dutch art critics, who said that his talent was limited outside of copying other artists' work.

One critic wrote that he was "a gifted technician who has made a sort of composite facsimile of the Renaissance school, he has every virtue except originality". Van Meegeren responded in a series of aggressive articles in De Kemphaan ("The Ruff"), a monthly periodical published by van Meegeren and journalist Jan Ubink from April 1928 until March 1930. Jonathan Lopez writes that Van Meegeren "denounced modern painting as 'art-Bolshevism' in the articles, described its proponents as a 'slimy bunch of woman-haters and negro-lovers,' and invoked the image of 'a Jew with a handcart' as a symbol for the international art market".

Van Meegeren set out to prove to the art critics that he could more than copy the Dutch Masters; he would produce a work to rival theirs.

The "perfect forgery"
In 1932, Van Meegeren moved to the village of Roquebrune-Cap-Martin with his wife. There he rented a furnished mansion called "Primavera" and set out to define the chemical and technical procedures that would be necessary to create his perfect forgeries. He bought authentic 17th-century canvases and mixed his own paints from raw materials (such as lapis lazuli, white lead, indigo, and cinnabar) using old formulas to ensure that they could pass as authentic. In addition, he created his own badger-hair paintbrushes similar to those that Vermeer was known to have used.

He came up with a scheme of using phenol formaldehyde (Bakelite) to cause the paints to harden after application, making the paintings appear as if they were 300 years old. Van Meegeren would first mix his paints with lilac oil, to stop the colours from fading or yellowing in heat. (This caused his studio to smell so strongly of lilacs that he kept a vase of fresh lilacs nearby so that visitors wouldn't be suspicious.) Then, after completing a painting, he would bake it at 100 °C to 120 °C to harden the paint, and then roll it over a cylinder to increase the cracks. Later, he would wash the painting in black India ink to fill in the cracks.

It took Van Meegeren six years to work out his techniques, but ultimately he was pleased with his work on both artistic and deceptive levels. Two of these trial paintings were painted as if by Vermeer: Lady Reading Music, after the genuine paintings Woman in Blue Reading a Letter at the Rijksmuseum in Amsterdam; and Lady Playing Music, after Vermeer's Woman With a Lute Near a Window hanging in the Metropolitan Museum of Art in New York City. Van Meegeren did not sell these paintings; both are now at the Rijksmuseum.

Following a journey to the 1936 Summer Olympics in Berlin, Van Meegeren painted The Supper at Emmaus. In 1934 Van Meegeren had bought a seventeenth century mediocre Dutch painting, The Awakening of Lazarus, and on this foundation he created his masterpiece à la Vermeer. The experts assumed that Vermeer had studied in Italy, so Van Meegeren used the version of Michelangelo Merisi da Caravaggio's Supper at Emmaus, located at Milan's Pinacoteca di Brera, as a model. He gave the painting to his friend, attorney C. A. Boon, telling him that it was a genuine Vermeer, and asked him to show it to Dr. Abraham Bredius, the art historian, in Monaco. In October 1932, Bredius had already published an article about two recently discovered alleged Vermeer paintings, which he defined as "Landscape" and "Man and Woman at a Spinet". He claimed the former to be a fake, and described it as "a landscape of the eighteenth century into which had been imported scraps of the 'View of Delft'" (mostly the Delft New Church's tower). The Man and Woman at a Spinet, instead, not only was judged as an "authentic Vermeer", but also "very beautiful", and "one of the finest gems of the master's œuvre". In September 1937, Bredius examined The Supper at Emmaus and, writing in The Burlington Magazine, he accepted it as a genuine Vermeer and praised it very highly as "the masterpiece of Johannes Vermeer of Delft". The usually required evidences, such as resilience of colours against chemical solutions, white lead analysis, x-rays images, micro-spectroscopy of the colouring substances, confirmed it to be an authentic Vermeer.

The painting was purchased by The Rembrandt Society for fl.520,000 (€235,000 or about €4,640,000 today), with the aid of wealthy shipowner Willem van der Vorm, and donated to the Museum Boijmans Van Beuningen in Rotterdam. In 1938, the piece was highlighted in a special exhibition in occasion of Queen Wilhelmina's Jubilee at a Rotterdam museum, along with 450 Dutch old masters dating from 1400 to 1800. A. Feulner wrote in the "Magazine for [the] History of Art", "In the rather isolated area in which the Vermeer picture hung, it was as quiet as in a chapel. The feeling of the consecration overflows on the visitors, although the picture has no ties to ritual or church", and despite the presence of masterpieces of Rembrandt and Grünewald, it was defined as "the spiritual centre" of the whole exhibition.

In 1938, Van Meegeren moved to Nice, buying a 12-bedroom estate at Les Arènes de Cimiez with the proceeds from the sale of the painting. On the walls of the estate hung several genuine Old Masters. Two of his better forgeries were made here, Interior with Card Players and Interior with Drinkers, both displaying the signature of Pieter de Hooch. During his time in Nice, he painted his Last Supper I in the style of Vermeer.

He returned to the Netherlands in September 1939 as the Second World War threatened. After a short stay in Amsterdam, he moved to the village of Laren in 1940. Throughout 1941, Van Meegeren issued his designs, which he published in 1942 as a large and luxurious book entitled Han van Meegeren: Teekeningen I (Drawings nr I). He also created several forgeries during this time, including The Head of Christ, The Last Supper II, The Blessing of Jacob, The Adulteress, and The Washing of the Feet—all in the manner of Vermeer. On 18 December 1943, he divorced his wife, but this was only a formality; the couple remained together, but a large share of his capital was transferred to her accounts as a safeguard against the uncertainties of the war.

In December 1943, the Van Meegerens moved to the exclusive Keizersgracht 321 in Amsterdam. His forgeries had earned him between 5.5 and 7.5 million guilders (or about US$25–30 million today). He used this money to purchase a large amount of real estate, jewellery, and works of art, and to further his luxurious lifestyle. In a 1946 interview, he told Marie Louise Doudart de la Grée that he owned 52 houses and 15 country houses around Laren, among them grachtenhuizen, mansions along Amsterdam's canals.

Hermann Göring

In 1942, during the German occupation of the Netherlands, one of Van Meegeren's agents sold the Vermeer forgery Christ with the Adulteress to Nazi banker and art dealer Alois Miedl. Experts could probably have identified it as a forgery; as Van Meegeren's health declined, so did the quality of his work. He chain-smoked, drank heavily, and became addicted to morphine-laced sleeping pills. However, there were no genuine Vermeers available for comparison, since most museum collections were in protective storage as a prevention against war damage.

Nazi Reichsmarschall Hermann Göring traded 137 looted paintings for Christ with the Adulteress. On 25 August 1943, Göring hid his collection of looted artwork, including Christ with the Adulteress, in an Austrian salt mine, along with 6,750 other pieces of artwork looted by the Nazis. On 17 May 1945, Allied forces entered the salt mine and Captain Harry Anderson discovered the painting.

In May 1945, the Allied forces questioned Miedl regarding the newly discovered Vermeer. Based on Miedl's confession, the painting was traced back to Van Meegeren. On 29 May 1945, he was arrested and charged with fraud and aiding and abetting the enemy. He was remanded to the Weteringschans prison as an alleged Nazi collaborator and plunderer of Dutch cultural property, threatened by the authorities with the death penalty. He labored over his predicament, but eventually confessed to forging paintings attributed to Vermeer and Pieter de Hooch. He exclaimed, "The painting in Göring's hands is not, as you assume, a Vermeer of Delft, but a Van Meegeren! I painted the picture!" It took some time to verify this, and Van Meegeren was detained for several months in the Headquarters of the Military Command at Herengracht 458 in Amsterdam.

Van Meegeren painted his last forgery between July and December 1945 in the presence of reporters and court-appointed witnesses: Jesus among the Doctors, also called Young Christ in the Temple in the style of Vermeer. After completing the painting, he was transferred to the fortress prison Blauwkapel. Van Meegeren was released from prison in January or February 1946.

Trial and prison sentence
The trial of Han van Meegeren began on 29 October 1947 in Room 4 of the Regional Court in Amsterdam. The collaboration charges had been dropped, since the expert panel had found that the supposed Vermeer sold to Hermann Göring had been a forgery and was, therefore, not the cultural property of the Netherlands. Public prosecutor H. A. Wassenbergh brought charges of forgery and fraud and demanded a sentence of two years in prison.

The court commissioned an international group of experts to address the authenticity of Van Meegeren's paintings. The commission included curators, professors, and doctors from the Netherlands, Belgium, and England, and was led by the director of the chemical laboratory at the Royal Museums of Fine Arts of Belgium, Paul B. Coremans. The commission examined the eight Vermeer and Frans Hals paintings which Van Meegeren had identified as forgeries. With the help of the commission, Dr. Coremans was able to determine the chemical composition of van Meegeren's paints.

He found that the paint contained the phenolformaldehyde resins Bakelite and Albertol as paint hardeners. A bottle had been found in Van Meegeren's studio. As Bakelite was not discovered until the 20th century, this proved that the paintings could not be genuine.

The commission also suggested that the dust in the craquelure was too homogeneous to be of natural origin. It appeared to come from India ink, which had accumulated even in areas that natural dirt or dust would never have reached. The paint had become so hard that alcohol, strong acids, and bases did not attack the surface, a clear indication that the surface had not been formed in a natural manner. The craquelure on the surface did not always match that in the ground layer, which would certainly have been the case with a natural craquelure. Thus, the test results obtained by the commission appeared to confirm that the works were forgeries created by Van Meegeren, but their authenticity continued to be debated by some of the experts until 1967 and 1977, when new investigative techniques were used to analyze the paintings (see below).

On 12 November 1947, the Fourth Chamber of the Amsterdam Regional Court found Han van Meegeren guilty of forgery and fraud, and sentenced him to one year in prison. The trial was widely covered in the media, and van Meegeren became a folk hero.

Death
While waiting to be moved to prison, Van Meegeren returned to his home, where his health continued to decline. During this last month of his life, he strolled freely around his neighbourhood.

Van Meegeren suffered a heart attack on 26 November 1947, the last day to appeal the ruling, and was rushed to the Valeriuskliniek, a hospital in Amsterdam. While at the hospital, he suffered a second heart attack on 29 December, and was pronounced dead at 5:00 pm on 30 December 1947 at the age of 58. Soon after his death, a plaster death mask was made, which was acquired by the Rijksmuseum in 2014. His family and several hundred of his friends attended his funeral at the Driehuis Westerveld Crematorium chapel. In 1948, his urn was buried in the general cemetery in the village of Diepenveen (municipality of Deventer).

Aftermath
After his death, the court ruled that Van Meegeren's estate be auctioned and the proceeds from his property and the sale of his counterfeits be used to refund the buyers of his works and to pay income taxes on the sale of his paintings. Van Meegeren had filed for bankruptcy in December 1945. On 5 and 6 September 1950, the contents of his Amsterdam house were auctioned, along with 738 other pieces of furniture and works of art, including numerous paintings by old and new masters from his private collection. The house was auctioned separately on 4 September.

The proceeds amounted to 123,000 guilders. Van Meegeren's unsigned The Last Supper I was bought for 2,300 guilders, while Jesus among the Doctors (which Van Meegeren had painted while in detention) sold for 3,000 guilders (about US$800, or about US$7,000 today). Today the painting hangs in a Johannesburg church. The sale of the entire estate amounted to 242,000 guilders (about US$60,000, or about US$500,000 today).

Throughout his trial and bankruptcy, Van Meegeren maintained that his second wife Jo had nothing to do with his forgeries. A large part of his considerable wealth had been transferred to her when they divorced, and the money would have been confiscated if she had been ruled to be an accomplice. Though some biographers believe she must have known the truth, her involvement was never proven and she was able to keep her substantial capital. Jo outlived her husband by many years, in luxury, until her death at the age of 91.

M. Jean Decoen's objection
M. Jean Decoen, a Brussels art expert and restorer, stated in his 1951 book he believed The Supper at Emmaus and The Last Supper II to be genuine Vermeers, and demanded that the paintings should again be examined. He also claimed that Van Meegeren used these paintings as a model for his forgeries. Daniel George Van Beuningen, the buyer of The Last Supper II, Interior with Drinkers, and The Head of Christ, demanded that Dr. Paul Coremans publicly admit that he had erred in his analysis. Coremans refused and Van Beuningen sued him, alleging that Coremans's wrongful branding of The Last Supper II diminished the value of his "Vermeer" and asking for compensation of £500,000 (about US$1.3 million, or about US$10 million today).

The first trial in Brussels was won by Coremans, because the court adopted the same reasoning of the court ruling at Van Meegeren's trial. A second trial was delayed owing to Van Beuningen's death on 29 May 1955. In 1958 the court heard the case on behalf of Van Beuningen's heirs. Coremans managed to give the definitive evidence of the forgeries by showing a photograph of a Hunting Scene, attributed to A. Hondius, exactly the same scene which was visible with X-ray under the surface of the alleged Vermeer's Last Supper. Moreover, Coremans brought a witness to the courtroom who confirmed that Van Meegeren bought the Hunt scene in 1940. The court found in favour of Coremans, and the findings of his commission were upheld.

Further investigations
In 1967, the Artists Material Center at Carnegie Mellon University in Pittsburgh examined several of the "Vermeers" in their collection, under the direction of Robert Feller and Bernard Keisch. The examination confirmed that several of their paintings were in fact created using materials invented in the 20th century. They concluded that they could be Van Meegeren forgeries. The test results obtained by the Carnegie Mellon team are summarized below.

Han van Meegeren knew that white lead was used during Vermeer's time, but he had to obtain his stocks through the modern colour trade. In the 17th century, lead was mined from deposits located in the Low Countries; however, by the 19th century, most lead was imported from Australia and the Americas, and differed both in isotope composition and in the content of trace elements. Dutch white lead was extracted from ores containing high levels of trace elements of silver and antimony, while the modern white lead used by Van Meegeren contained neither, as those elements are separated from the lead during the modern smelting process.

Forgeries in which modern lead or white lead pigment has been used can be recognized by using a technique called Pb(Lead)-210-Dating. Pb-210 is a naturally occurring radioactive isotope of lead that is part of the uranium-238 Radioactive decay series, and has a half-life of 22.3 years. To determine the amount of Pb-210, the alpha radiation emitted by another element, polonium-210 (Po-210), is measured. Thus it is possible to estimate the age of a painting, within a few years' span, by extrapolating the Pb-210 content present in the paint used to create the painting.

The white lead in the painting The Supper at Emmaus had polonium-210 values of 8.5±1.4 and radium-226 (part of the uranium-238 radioactive decay series) values of 0.8±0.3. In contrast, the white lead found in Dutch paintings from 1600 to 1660 had polonium-210 values of 0.23±0.27 and radium-226 values of 0.40±0.47.

In 1977, another investigation was undertaken by the States forensic labs of the Netherlands using up-to-date techniques, including gas chromatography, to formally confirm the origin of six van Meegeren forgeries that had been alleged to be genuine Vermeers, including the Emmaus and the Last Supper. The conclusions of the 1946 commission were again reaffirmed and upheld by the Dutch judicial system.

In 1998, A&E ran a program called Scams, Schemes & Scoundrels highlighting Van Meegeren's life and art forgeries, many of which had been confiscated as Nazi loot. The program was hosted by skeptic James Randi.

In July 2011, the BBC TV programme Fake or Fortune investigated a copy of Dirck van Baburen's The Procuress owned by the Courtauld Institute. Opinion had been divided as to whether it was a 17th-century studio work or a Van Meegeren fake. The programme used chemical analysis of the paint to show that it contained bakelite and thus confirmed that the painting was a 20th-century fake.

Legacy

In 2008, Harvard-trained art historian Jonathan Lopez published The Man Who Made Vermeers, Unvarnishing the Legend of Master Forger Han Van Meegeren. His extensive research confirmed that Van Meegeren started to make forgeries, not so much because of feeling misunderstood and undervalued by art critics as some maintain, but for the income that it generated, which he needed to support his addictions and lavish lifestyle.

Van Meegeren's father was said to have once told Van Meegeren, "You are a cheat and always will be." Van Meegeren sent a signed copy of his own art book to Adolf Hitler, which turned up in the Reich Chancellery in Berlin complete with an inscription (in German): "To my beloved Führer in grateful tribute, from H. van Meegeren, Laren, North Holland, 1942". He only admitted the signature was his own, although the entire inscription was by the same hand. He bought up homes of several departed Jewish families in Amsterdam and held lavish parties while much of the country was hungry. On the other hand, his brothers and sisters perceived him as loyal, generous, and affectionate, and he was always loving and helpful to his own children.

Van Meegeren continued to paint after he was released from prison, signing his works with his own name. His new-found profile ensured quick sales of his new paintings, often selling at prices that were many times higher than before he had been unmasked as a forger. Van Meegeren also told the news media that he had "an offer from a Manhattan gallery to come to the U.S. and paint portraits 'in the 17th-century manner' at US$6,000 a throw".

A Dutch opinion poll conducted in October 1947 placed Han van Meegeren's popularity second in the nation, behind only the Prime Minister's and slightly ahead of Prince Bernhard, the husband of Princess Juliana. The Dutch people viewed Van Meegeren as a cunning trickster who had successfully fooled the Dutch art experts and, more importantly, Hermann Göring himself. In fact, according to a contemporary account, Göring was informed that his "Vermeer" was actually a forgery and "[Göring] looked as if for the first time he had discovered there was evil in the world". Lopez, however, suggests Göring may never have known the painting was a fake.

Lopez argued that Han van Meegeren's defence during his trial in Amsterdam was a masterpiece of trickery, forging his own personality into a true Dutchman eager to trick his critics and also the Dutch people by pretending that he sold his fake Vermeer to Göring because he wanted to teach the Nazi a lesson. Van Meegeren remains one of the most ingenious art counterfeiters of the 20th century. After his trial, however, he declared, "My triumph as a counterfeiter was my defeat as [a] creative artist."

Known forgeries

List of known forgeries by Han van Meegeren (unless specified differently, they are after Vermeer):
 * A counterpart to Laughing Cavalier after Frans Hals (1923) once the subject of a scandal in The Hague in 1923, its present whereabouts is unknown.
 * The Happy Smoker after Frans Hals (1923) hangs in the Groninger Museum in the Netherlands
 * Man and Woman at a Spinet 1932 (perhaps without misleading intentions, sold to Amsterdam banker, Dr. Fritz Mannheimer)
 * Lady reading a letter 1935–1936 (unsold, on display at the Rijksmuseum)
 * Lady playing a lute and looking out the window 1935–1936 (unsold, on display at the Rijksmuseum)
 * Portrait of a Man 1935–1936 in the style of Gerard ter Borch (unsold, on display at the Rijksmuseum)
 * Woman Drinking after Frans Hals (version of Malle Babbe) 1935–1936 (unsold, on display at the Rijksmuseum.)
 * The Supper at Emmaus, 1936–1937 (sold to the Boymans for 520,000–550,000 guldens, about US$300,000 or US$4 Million today)
 * Interior with Drinkers 1937–1938 (sold to D G. van Beuningen for 219,000–220,000 guldens about US$120,000 or US$1.6 million today)
 * The Last Supper I, 1938–1939
 * Interior with Cardplayers 1938–1939 (sold to W. van der Vorm for 219,000–220,000 guldens US$120,000 or US$1.6 million today)
 * The Head of Christ, 1940–1941 (sold to D G. van Beuningen for 400,000–475,000 guldens about US$225,000 or US$3.25 million today)
 * The Last Supper II, 1940–1942 (sold to D G. van Beuningen for 1,600,000 guldens about US$600,000 or US$7 million today)
 * The Blessing of Jacob 1941–1942 (sold to W. van der Vorm for 1,270,000 guldens about US$500,000 or US$5.75 million today)
 * Christ with the Adulteress 1941–1942 (sold to Hermann Göring for 1,650,000 guldens about US$624,000 or US$6.75 million today, now in the public collection of Museum de Fundatie )
 * The Washing of the Feet 1941–1943 (sold to the Netherlands state for 1,250,000–1,300,000 guldens about US$500,000 or US$5.3 million today, on display at the Rijksmuseum)
 * Jesus among the Doctors September 1945 (painted during trial under Court's control, and sold at auction for 3,000 guldens, about US$800 or US$7,000 today)
 * The Procuress given to the Courtauld Institute as a fake in 1960 and confirmed as such by chemical analysis in 2011.

Posthumously, Van Meegeren's forgeries have been shown in exhibitions around the world, including exhibitions in Amsterdam (1952), Basel (1953), Zürich (1953), Haarlem in the Kunsthandel de Boer (1958), London (1961), Rotterdam (1971), Minneapolis (1973), Essen (1976–1977), Berlin (1977), (1985), New York (1987), Berkeley, CA (1990), Munich (1991), Rotterdam (1996), The Hague (1996) and more recently at the Haagse Kunstkring, The Hague (2004) and Stockholm (2004), and have thus been made broadly accessible to the public.

Potential forgeries
It is possible that other fakes hang in art collections all over the world. Jacques van Meegeren suggested that his father had created a number of other forgeries, during interviews with journalists regarding discussions with his father. Some of these possible forgeries include:
 * Boy with a Little Dog and The Rommelpotspeler after Frans Hals. The Frans Hals catalogue by Frans L. M. Dony mentions four paintings by this name attributed to Frans Hals or the "school of Frans Hals".
 * A counterpart to Vermeer's Girl with a Pearl Earring. A painting called Smiling Girl hangs in the National Gallery of Art in Washington, D.C. (bequest Andrew W. Mellon) which has been recognized by the museum as a fake. It was attributed to Theo van Wijngaarden, friend and partner of Van Meegeren, but may have been painted by Van Meegeren.
 * Lady with a Blue Hat after Vermeer which was sold to Baron Heinrich Thyssen in 1930. Its present whereabouts are unknown. It is often referred to as the “Greta Garbo” Vermeer.

Original artwork
Van Meegeren was a prolific artist and produced thousands of original paintings in a number of diverse styles. This wide range in painting and drawing styles often irritated art critics. Some of his typical works are classical still lifes in convincing 17th century manner, Impressionistic paintings of people frolicking on lakes or beaches, jocular drawings where the subject is drawn with rather odd features, Surrealistic paintings with combined fore- and backgrounds. Van Meegeren's portraits, however, are probably his finest works.

Among his original works is his famous Deer, pictured above. Other works include his prize-winning St. Laurens Cathedral; a Portrait of the actress Jo Oerlemans (his second wife); his Night Club; from the Roaring Twenties; the cheerful watercolor A Summer Day on the Beach and many others.

The forger, forged
Van Meegeren's own work rose in price after he had become known as a forger, and it consequently became worthwhile to fake his paintings, as well. Existing paintings obtained a signature "H. van Meegeren", or new pictures were made in his style and falsely signed. When Van Meegeren saw a fake like that, he ironically remarked that he would have adopted them if they had been good enough, but regrettably he had not yet seen one.

Later on, however, his son Jacques van Meegeren started to fake his father's work. He made paintings in his father's style – although of much lower quality – and was able to place a perfect signature on these imitations. Many fakes – both by Jacques and by others – are still on the market. They can be recognized by their low pictorial quality, but are not always regarded as such.

In media
Han van Meegeren was played by Guy Pearce in the movie The Last Vermeer, which tells the story of the investigation into his sale of the painting "Jesus and the Adulteress" to Nazi officer Hermann Göring. The movie was based on the book The Man Who Made Vermeers, Unvarnishing the Legend of Master Forger Han Van Meegeren, by Jonathan Lopez.

title: Han van Meegeren


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List of business schools in Canada

The following is a list of business schools in Canada, organized by province.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: List of business schools in Canada


text:
Talk:Death metal

People really don't know death metal come along way.
Deathmetal come along way. back before our time. 73.34.107.203 (talk) 01:57, 29 November 2021 (UTC)

1983-4
This is Jeff from Possessed. These years are cooked. The media has always misled the fans because of a few revisionists and the actual history of Death Metal is actually better than the false claims. Put simply, I think we came too early and so many people were unable to understand what was going on. Of course, after I was shot and people thought I was never coming back Possessed went from the only Death Metal band to being massively downplayed. So many band labels, knowing there is a certain intrinsic value that comes with being the “1st “ began spinning stories in wn attempt to cash in during my absence. 1983 start date has went from just Possessed to a  multitude of workarounds. To say that “Death formed in 83” is simply not true. According to Kam Lee “While Mantas we’re around in 83 they were a Venom cover band with one original that sounded like Venom “Chuck joined Mantas which quickly became the mighty Death.

Keep in mind, every member of Death also knew/knows what happened. Chuck was extremely taken with Possessed, Death Metal. Possessed were apples to oranges different than anything else at that tine.

In 83-84 Possessed were so far over the top. Back then it was like the most brutal death metal of today because at that time we were literally the heaviest fastest band in the planet. And. Ring “the heaviest” very quickly and early on became the benchmark. Once we opened Pandora’s box bands started getting heavier and heavier in a race to become the new heaviest. And with this Death Metal became more than Possessed,

I am certainly not trying to claim all things Death Metal. I just want people to know the truth. Which is that Possessed were unequivocally the first Death Metal band and created the original Death Metal style.

I was robbed of a big part of my life and I love Death Metal. It’s history.

It’s probably worth pointing out that not one of these bands that claim to have “invented Death Metal” would never say that to my face. Especially if the were actually there as well, there are still far too many of us around that were there and know the truth.

I am still trying to figure out how “Noise Records” is being attributed to “creating death metal” a year after we did. In fact, it’s a bull shit logic to say that because there are heavier bands Possessed should be blotted from what we did.

That logic goes both ways. And truthfully, since Possessed were the very first, it could also be said that it’s the purest form.

Anyone who claims to have “invented” DM before Possessed are posing hard and they know it. We would have never tried to sound it take credit for another bands efforts.

At the same time the most important thing is that Death Metal as a genre, and it’s true I brainwashed history be kept alive.

Chuck made no secret that he modeled Death after Possessed. He was in correspondence with me and literally moved into the California Possessed Fan Club President’s house (Krystal Mahoney) in Antioch in order to be closer to us. Chuck and I became friends and was truly one of the first people that followed in our footsteps. He was proud of me and I am proud of him. The only “rivalry” stemmed from greedy revisionist managers, labels and the lucrative business of the industry.

Possessed was the first, and this means we will forever be downplayed and despised by everyone who thinks newer is older.

Of course, I see it in the old school pre-cancel culture way. I support ALL Death Metal bands. Being first is both a blessing and a curse.

Long live Death Metal. May it’s true history be known and brought to light. Death to posers. 2601:200:4000:1D80:C938:CB87:15D8:1DC5 (talk) 19:40, 10 January 2022 (UTC)

Not to be confused with
Wanted to check on this - the "Not to be confused with" template says it's to be used as below:

"This hatnote is generally used when readers have misspelled their desired title, and the error would be apparent by simply displaying the alternative term without further explanation. For example, consider a reader looking for the punctuation mark who instead ends up at coma:"

Does this really apply to deathrock in this article? Deathrock certainly isn't a misspelling, and have to be honest, I don't have any idea what deathrock is - I'd definitely need further explanation. Does that deserve a section in the article under associated styles rather than a misuse of the "Not to be confused with" element? Random name (talk) 22:12, 9 July 2022 (UTC)

Goregrind
On this page there is some criticism regarding the Deathgrind/goregrind part. I want to add something to that critique. It's too bad the source, Terrorizer Magazine 181, is not readily available. I'm writing a piece about goregrind (for my blog) and came to the conclusion the genre is not focused on complexity at all. It's raw and brutal like grindcore, but often it's less serious, and more sloppy and crude than grindcore. The death metal influence is mainly impacting the lyrics. This sentence might not be appropriate for goregrind: "brevity of grindcore with the complexity of death metal". I've bought Terrorizer Magazine 181 from Ebay, will have to wait to check the article. Kameejl (Talk) 22:07, 8 February 2023 (UTC)

 * Just remember that your view as a wikipedian fails WP:RS because of WP:NPOV and WP:OR, so if it were to be included on the article it might have reliable third-party sources to back it up. ABC paulista (talk) 02:17, 9 February 2023 (UTC)

 * Haven't I said I bought the sourced magazine to check if the claim was even made in the source? I think it's WP:NPOV and WP:OR to begin with. Kameejl (Talk) 06:29, 9 February 2023 (UTC)
 * In the meantime https://www.academia.edu/764000/BRUTAL_BELONGING_IN_MELBOURNES_GRINDCORE_SCENE
 * "Grindcore adopted death-metal’s vocal element and loud volumes, but merged these forms with punk sartorialism and politics. Bands play short, fast songs, characterized by punk riffs, extremely fast drumming (blastbeats) and screamed vocals. Unlike heavy metal, and death metal, grindcore is not melodic and usually does not feature guitar solos (cf. Purcell, 2003; Walser, 1993; Weinstein, 2000). However, similar to death metal, grindcore lyrics are predominantly violent. Yet, grindcore’s aggression largely targets the machinations of late-capitalist culture.7 Radical politics still forms a key element of contemporary grindcore music.8 Nevertheless, there has been a recent shift toward gorier imagery, in the ‘‘gore-grind’’ subgenre. Here, lyrics are simply violent for the sake of violence, rather than violence with a radical message (see albums by Fuck y I’m Dead, 2001; Undinism, 2002; Vaginal Carnage, 2002). However, gore-grind music remains in the punk style." Kameejl (Talk) 06:50, 9 February 2023 (UTC)

 * Another quote https://www.ckz.si/arhiv/274/CKZ_274_Notranja_net-199-214.pdf "Both technical death metal and powerviolence (PW) can be seen as an opposite to porno-gore grind (PGG). Namely, contrary to the above-mentioned technical skill, PGG musically is based on a very simple style of usually a groovy metalized polka dance rhythm that is “brutalized” by blast-beats and the vocals of bubbling, grunting or (pig)squealing that represent the main characteristic"of the sub-genre."

 * More https://books.google.nl/books?id=4BEeEAAAQBAJ&printsec=frontcover&hl=nl&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false "(Plazola 2015: 147) Plazola's study applies these characteristics that he attributes to grindcore to subgenres such as pornogrind and goregrind, 12 the latter considered to be more influenced by punk and hardcore scenes (Overell 2010..." Kameejl (Talk) 11:28, 9 February 2023 (UTC)
 * I was talking about your assesement of the genre, your "conclusion", which the second source does seem to support it. The other two just state that the genre have more punk charactersitics, which tells us nothing about its complexity. ABC paulista (talk) 16:47, 9 February 2023 (UTC)
 * The problem is that hardly anyone can verify the claim goregrind has "the complexity of death metal". I assume it's not in the source, because it's demonstrably untrue. Hence, I think the claim doesn't need to be disproven. It can be deleted and a (verifiable) source can be used to make a valid claim about the genre, and no, it doesn't need to tell us anything about its complexity. Just to be on the safe side, I bought the magazine, I'll have to wait for it to be shipped. Kameejl (Talk) 18:58, 9 February 2023 (UTC)
 * It should be noted that that subsection deals with multiple combinations of Grindcore and Death Metal and isn't focused on Goregrind, so the statements contained there might not be appliable to all the iterations, but what is generally observed in such combinations. In all, I think that this issue might be easier resolved by tweaking the phrase a bit, just stating that these genres combine characteristics of Grindcore with Death metal, without being more specific about it. ABC paulista (talk) 21:56, 9 February 2023 (UTC)
 * Easier done than said. I removed a few words Kameejl (Talk) 22:25, 9 February 2023 (UTC)
 * WP:BOLD, that's the spirit. ABC paulista (talk) 22:42, 9 February 2023 (UTC)

Do not restore Cannibal Corpse as a band that exemplifies brutal death metal
Cannibal Corpse is a precursor to brutal death metal, and are not themselves a brutal death metal band. See this book, which describes their first two albums as precursors to brutal death metal (meaning not themselves brutal death metal), and sources do not generally describe their later albums as brutal death metal either. —Alalch E. 00:26, 29 October 2023 (UTC)

 * A student newspaper article was used to support the claim that Cannibal Corpse exemplifies brutal death metal (being listed in a short list of bands in this one-paragraph overview of the subgenre, automatically indicates that the band exemplifies the sound). However, a student newspaper is a not a reliable source for the sensitive matter of ascribing precise genre labels to bands, which requires expertise in the subject area by the author; see WP:RSSM: Reputable student media outlets, such as The Harvard Crimson, are considered generally reliable sources for news on their school and local community. They can sometimes be considered reliable on other topics, although professional sources are typically preferred ... (emphasis mine). —Alalch E. 00:30, 29 October 2023 (UTC)
 * Just because a band is considered as a percursor of a genre doesn't mean that itself can't be part of it, we have examples of bands being considered both like Venom is for Black metal, or Melvins is for Sludge metal. Also, Kerrang describes Cannibal Corpse as Brutal death metal multiple times. ABC paulista (talk) 00:41, 29 October 2023 (UTC)
 * There are problems with that source.
 * Eaten Back To Life (1990, first album) is not described as brutal death metal, and is described as an incredible old-school death metal record by a killer band...who just aren’t there yet
 * Butchered At Birth (1991, second album) is not described as brutal death metal
 * Tomb Of The Mutilated (1992, third album) is not described as brutal death metal
 * The Bleeding (1994, fourth album) is described as The Bleeding is Cannibal Corpse’s “mainstream” album and Stripped, Raped, And Strangled is in many ways the band’s most accessible song, so "manstream" and "accessible", and then it continues with the following odd remark: At the same time, it’s hard to argue that this album is anything but pure brutal death metal. To me, this does not mean that the reviewer actually considers this album to belong in the brutal death metal subgenre stylistically, but is using the words "brutal death metal" to contrast the heaviness and the brutality of the album with earlier statements how it's more accessible than their previous albums.
 * The construction of that sentence is obviously rhetorical as uses the word "brutal" to compensete for previously used "mainstream" and "accessible". To me, this does not support the claim that Cannibal Corpse is an exemplifying the brutal death metal subgenre. Ths is just not the right type of writing that we should use for precise claims about a subgenre. —Alalch E. 01:21, 29 October 2023 (UTC)
 * Being "mainstream" and "accessible" doesn't automatically remove its belonging to a specific genre, because they are two separated and mostly unrelated concepts. Not being accessible or mainstream isn't a prerequisite to be a Brutal death metal band, since this designation describes the bean's sound, the kind of music they play, not the amount of popularity they can achieve, so when they say that The Bleeding is "anything but pure brutal death metal", they say that the album still belongs to the genre regardless of its popularity.
 * Also, for a band to be considered part of a genre doesn't mean that every single album has to have the same designation, the band just have to be designated as such by a reliable source to satisfy WP:EXPLICITGENRE. It's not necessary to pinpoint where the designation is justified, being recognized by reputable people/institutions is enough. ABC paulista (talk) 02:25, 29 October 2023 (UTC)
 * Pinging other editors who have recently made edits to this content: Please weigh in. Do sources support the claim that Cannibal Corpse is a band that exemplifies brutal death metal to such a degree that we would list them as a prime example of the subgenre along with only a handful of other bands that exemplify the genre (Dying Fetus, Suffocation, Cryptopsy, and Skinless)? —Alalch E. 01:28, 29 October 2023 (UTC)
 * Consequence.net said that the band is known for their "brutal palate", that they "excel at making brutal death metal memorable, if not palatable," and that they have a "legacy of brutality." Satisfies WP:EXPLICITGENRE. Seems pretty solid to me. Binksternet (talk) 01:34, 29 October 2023 (UTC)
 * The book Death Metal Music: The Passion and Politics of a Subculture state that With little contention, Cannibal Corpse's first album, Eaten Back to Life, was deemed pure, brutal Death Metal, the book Extreme Metal II state that Buffalo band Cannibal Corpse are perhaps the most devoted brutal death metal act in this book, rarely diverging from the path of the blastbeat and the throaty roar., and both this book and Masterclass directly cites it as a Brutal Death metal band. ABC paulista (talk) 02:41, 29 October 2023 (UTC)

title: Talk:Death metal


text:
Flood

A flood is an overflow of water (or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding. Examples for human changes are land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees. Global environmental issues also influence causes of floods, namely climate change which causes an intensification of the water cycle and sea level rise. For example, climate change makes extreme weather events more frequent and stronger. This leads to more intense floods and increased flood risk.

The types of floods include areal flooding, riverine flooding, coastal flooding and urban flooding. There is also the intentional flooding of land that would otherwise remain dry. This may take place for agricultural, military, or river-management purposes. For example, agricultural flooding may occur in preparing paddy fields for the growing of semi-aquatic rice in many countries.

Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean. In these cases, the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries. Flooding may also occur due to an accumulation of rainwater on saturated ground. This is called an areal flood. The size of a lake or other body of water naturally varies with seasonal changes in precipitation and snow melt. Those changes in size are however not considered a flood unless they flood property or drown domestic animals.

Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if these buildings are in the natural flood plains of rivers. People could avoid riverine flood damage by moving away from rivers. However, people in many countries have traditionally lived and worked by rivers because the land is usually flat and fertile. Also, the rivers provide easy travel and access to commerce and industry.

Flooding can damage property and also lead to secondary impacts. These include in the short term an increased spread of waterborne diseases and vector-bourne disesases, for example those diseases transmitted by mosquitos. Flooding can also lead to long-term displacement of residents. Floods are an area of study of hydrology and hydraulic engineering.

Areal flooding
Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more rapidly than it can either infiltrate or run off. The excess accumulates in place, sometimes to hazardous depths. Surface soil can become saturated, which effectively stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration also is slow to negligible through frozen ground, rock, concrete, paving, or roofs. Areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope. Endorheic basins may experience areal flooding during periods when precipitation exceeds evaporation.

River flooding
Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the world's largest rivers. When overland flow occurs on tilled fields, it can result in a muddy flood where sediments are picked up by run off and carried as suspended matter or bed load. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, ice, debris, or beaver dams.

Slow-rising floods most commonly occur in large rivers with large catchment areas. The increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, or tropical cyclones. However, large rivers may have rapid flooding events in areas with dry climates, since they may have large basins but small river channels, and rainfall can be very intense in smaller areas of those basins. Rapid flooding events, including flash floods, more often occur on smaller rivers, rivers with steep valleys, rivers that flow for much of their length over impermeable terrain, or normally-dry channels. The cause may be localized convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flash flood killed eight people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the flow rate increased from about 50 to 1500 ft3/s in just one minute. Two larger floods occurred at the same site within a week, but no one was at the waterfall on those days. The deadly flood resulted from a thunderstorm over part of the drainage basin, where steep, bare rock slopes are common and the thin soil was already saturated.

Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere. In that setting, the first flood water to arrive is depleted as it wets the sandy stream bed. The leading edge of the flood thus advances more slowly than later and higher flows. As a result, the rising limb of the hydrograph becomes ever quicker as the flood moves downstream, until the flow rate is so great that the depletion by wetting soil becomes insignificant.

Coastal flooding
Coastal areas may be flooded by storm surges combining with high tides and large wave events at sea, resulting in waves over-topping flood defenses or in severe cases by tsunami or tropical cyclones. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category. A storm surge is "an additional rise of water generated by a storm, over and above the predicted astronomical tides". Due to the effects of climate change (e.g. sea level rise and an increase in extreme weather events) and an increase in the population living in coastal areas, the damage caused by coastal flood events has intensified and more people are being affected.

Flooding in estuaries is commonly caused by a combination of storm surges caused by winds and low barometric pressure and large waves meeting high upstream river flows.

Intentional floods
The intentional flooding of land that would otherwise remain dry may take place for agricultural, military or river-management purposes. This is a form of hydraulic engineering. Agricultural flooding may occur in preparing paddy fields for the growing of semi-aquatic rice in many countries. Flooding for river management may occur in the form of diverting flood waters in a river at flood stage upstream from areas that are considered more valuable than the areas that are sacrificed in this way. This may be done ad hoc, or permanently, as in the so-called overlaten (literally "let-overs"), an intentionally lowered segment in Dutch riparian levees, like the Beerse Overlaat in the left levee of the Meuse between the villages of Gassel and Linden, North Brabant.

Military inundation creates an obstacle in the field that is intended to impede the movement of the enemy. This may be done both for offensive and defensive purposes. Furthermore, in so far as the methods used are a form of hydraulic engineering, it may be useful to differentiate between controlled inundations and uncontrolled ones. Examples for controlled inundations include those in the Netherlands under the Dutch Republic and its successor states in that area and exemplified in the two Hollandic Water Lines, the Stelling van Amsterdam, the Frisian Water Line, the IJssel Line, the Peel-Raam Line, and the Grebbe line in that country).

To count as controlled, a military inundation has to take the interests of the civilian population into account, by allowing them a timely evacuation, by making the inundation reversible, and by making an attempt to minimize the adverse ecological impact of the inundation. That impact may also be adverse in a hydrogeological sense if the inundation lasts a long time.

Examples for uncontrolled inundations are the second Siege of Leiden during the first part of the Eighty Years' War, the flooding of the Yser plain during the First World War, and the Inundation of Walcheren, and the Inundation of the Wieringermeer during the Second World War).

Causes
Floods are caused by many factors or a combination of any of these generally prolonged heavy rainfall (locally concentrated or throughout a catchment area), highly accelerated snowmelt, severe winds over water, unusual high tides, tsunamis, or failure of dams, levees, retention ponds, or other structures that retained the water. Flooding can be exacerbated by increased amounts of impervious surface or by other natural hazards such as wildfires, which reduce the supply of vegetation that can absorb rainfall.

During times of rain, some of the water is retained in ponds or soil, some is absorbed by grass and vegetation, some evaporates, and the rest travels over the land as surface runoff. Floods occur when ponds, lakes, riverbeds, soil, and vegetation cannot absorb all the water.

This has been exacerbated by human activities such as draining wetlands that naturally store large amounts of water and building paved surfaces that do not absorb any water. Water then runs off the land in quantities that cannot be carried within stream channels or retained in natural ponds, lakes, and human-made reservoirs. About 30 percent of all precipitation becomes runoff and that amount might be increased by water from melting snow.

River flooding is often caused by heavy rain, sometimes increased by melting snow. A flood that rises rapidly, with little or no warning, is called a flash flood. Flash floods usually result from intense rainfall over a relatively small area, or if the area was already saturated from previous precipitation.

Periodic floods occur on many rivers, forming a surrounding region known as the flood plain. Even when rainfall is relatively light, the shorelines of lakes and bays can be flooded by severe winds—such as during hurricanes—that blow water into the shore areas.

Upslope factors
The amount, location, and timing of water reaching a drainage channel from natural precipitation and controlled or uncontrolled reservoir releases determines the flow at downstream locations. Some precipitation evaporates, some slowly percolates through soil, some may be temporarily sequestered as snow or ice, and some may produce rapid runoff from surfaces including rock, pavement, roofs, and saturated or frozen ground. The fraction of incident precipitation promptly reaching a drainage channel has been observed from nil for light rain on dry, level ground to as high as 170 percent for warm rain on accumulated snow.

Most precipitation records are based on a measured depth of water received within a fixed time interval. Frequency of a precipitation threshold of interest may be determined from the number of measurements exceeding that threshold value within the total time period for which observations are available. Individual data points are converted to intensity by dividing each measured depth by the period of time between observations. This intensity will be less than the actual peak intensity if the duration of the rainfall event was less than the fixed time interval for which measurements are reported. Convective precipitation events (thunderstorms) tend to produce shorter duration storm events than orographic precipitation. Duration, intensity, and frequency of rainfall events are important to flood prediction. Short duration precipitation is more significant to flooding within small drainage basins.

The most important upslope factor in determining flood magnitude is the land area of the watershed upstream of the area of interest. Rainfall intensity is the second most important factor for watersheds of less than approximately 30 sqmi. The main channel slope is the second most important factor for larger watersheds. Channel slope and rainfall intensity become the third most important factors for small and large watersheds, respectively.

Time of Concentration is the time required for runoff from the most distant point of the upstream drainage area to reach the point of the drainage channel controlling flooding of the area of interest. The time of concentration defines the critical duration of peak rainfall for the area of interest. The critical duration of intense rainfall might be only a few minutes for roof and parking lot drainage structures, while cumulative rainfall over several days would be critical for river basins.

Downslope factors
Water flowing downhill ultimately encounters downstream conditions slowing movement. The final limitation in coastal flooding lands is often the ocean or some coastal flooding bars which form natural lakes. In flooding low lands, elevation changes such as tidal fluctuations are significant determinants of coastal and estuarine flooding. Less predictable events like tsunamis and storm surges may also cause elevation changes in large bodies of water. Elevation of flowing water is controlled by the geometry of the flow channel and, especially, by depth of channel, speed of flow and amount of sediments in it Flow channel restrictions like bridges and canyons tend to control water elevation above the restriction. The actual control point for any given reach of the drainage may change with changing water elevation, so a closer point may control for lower water levels until a more distant point controls at higher water levels.

Effective flood channel geometry may be changed by growth of vegetation, accumulation of ice or debris, or construction of bridges, buildings, or levees within the flood channel.

Coincidence
Extreme flood events often result from coincidence such as unusually intense, warm rainfall melting heavy snow pack, producing channel obstructions from floating ice, and releasing small impoundments like beaver dams. Coincident events may cause extensive flooding to be more frequent than anticipated from simplistic statistical prediction models considering only precipitation runoff flowing within unobstructed drainage channels. Debris modification of channel geometry is common when heavy flows move uprooted woody vegetation and flood-damaged structures and vehicles, including boats and railway equipment. Recent field measurements during the 2010–11 Queensland floods showed that any criterion solely based upon the flow velocity, water depth or specific momentum cannot account for the hazards caused by velocity and water depth fluctuations. These considerations ignore further the risks associated with large debris entrained by the flow motion.

Negative impacts
Floods can also be a huge destructive power. When water flows, it has the ability to demolish all kinds of buildings and objects, such as bridges, structures, houses, trees, and cars. Economical, social and natural environmental damages are common factors that are impacted by flooding events and the impacts that flooding has on these areas can be catastrophic.

There have been numerous flood incidents around the world which have caused devastating damage to infrastructure, the natural environment and human life. Flood risks can be defined as the risk that floods pose to individuals, property and the natural landscape based on specific hazards and vulnerability. The extent of flood risks can impact the types of mitigation strategies required and implemented.

Floods can have devastating impacts to human societies. Flooding events worldwide are increasing in frequency and severity, leading to increasing costs to societies. A large amount of the world's population lives in close proximity to major coastlines, while many major cities and agricultural areas are located near floodplains. There is significant risk for increased coastal and fluvial flooding due to changing climatic conditions.

Catastrophic riverine flooding can result from major infrastructure failures, often the collapse of a dam. It can also be caused by drainage channel modification from a landslide, earthquake or volcanic eruption. Examples include outburst floods and lahars. Tsunamis can cause catastrophic coastal flooding, most commonly resulting from undersea earthquakes.

Economic impacts
The primary effects of flooding include loss of life and damage to buildings and other structures, including bridges, sewerage systems, roadways, and canals. The economic impacts caused by flooding can be severe.

Every year flooding causes countries billions of dollars worth of damage that threatens the livelihood of individuals. As a result, there is also significant socio-economic threats to vulnerable populations around the world from flooding. For example, in Bangladesh in 2007, a flood was responsible for the destruction of more than one million houses. And yearly in the United States, floods cause over $7 billion in damage. Flood waters typically inundate farm land, making the land unworkable and preventing crops from being planted or harvested, which can lead to shortages of food both for humans and farm animals. Entire harvests for a country can be lost in extreme flood circumstances. Some tree species may not survive prolonged flooding of their root systems.

Flooding in areas where people live also has significant economic implications for affected neighborhoods. In the United States, industry experts estimate that wet basements can lower property values by 10–25 percent and are cited among the top reasons for not purchasing a home. According to the U.S. Federal Emergency Management Agency (FEMA), almost 40 percent of small businesses never reopen their doors following a flooding disaster. In the United States, insurance is available against flood damage to both homes and businesses.

Economic hardship due to a temporary decline in tourism, rebuilding costs, or food shortages leading to price increases is a common after-effect of severe flooding. The impact on those affected may cause psychological damage to those affected, in particular where deaths, serious injuries and loss of property occur.

Health impacts
Fatalities connected directly to floods are usually caused by drowning; the waters in a flood are very deep and have strong currents. Deaths do not just occur from drowning, deaths are connected with dehydration, heat stroke, heart attack and any other illness that needs medical supplies that cannot be delivered.

Injuries can lead to an excessive amount of morbidity when a flood occurs. Injuries are not isolated to just those who were directly in the flood, rescue teams and even people delivering supplies can sustain an injury. Injuries can occur anytime during the flood process; before, during and after. During floods accidents occur with falling debris or any of the many fast moving objects in the water. After the flood rescue attempts are where large numbers injuries can occur.

Communicable diseases are increased due to many pathogens and bacteria that are being transported by the water.There are many waterborne diseases such as cholera, hepatitis A, hepatitis E and diarrheal diseases, to mention a few. Gastrointestinal disease and diarrheal diseases are very common due to a lack of clean water during a flood. Most of clean water supplies are contaminated when flooding occurs. Hepatitis A and E are common because of the lack of sanitation in the water and in living quarters depending on where the flood is and how prepared the community is for a flood.

When floods hit, people lose nearly all their crops, livestock, and food reserves and face starvation.

Floods also frequently damage power transmission and sometimes power generation, which then has knock-on effects caused by the loss of power. This includes loss of drinking water treatment and water supply, which may result in loss of drinking water or severe water contamination. It may also cause the loss of sewage disposal facilities. Lack of clean water combined with human sewage in the flood waters raises the risk of waterborne diseases, which can include typhoid, giardia, cryptosporidium, cholera and many other diseases depending upon the location of the flood.

Damage to roads and transport infrastructure may make it difficult to mobilize aid to those affected or to provide emergency health treatment.

Flooding can cause chronically wet houses, leading to the growth of indoor mold and resulting in adverse health effects, particularly respiratory symptoms. Respiratory diseases are a common after the disaster has occurred. This depends on the amount of water damage and mold that grows after an incident. Research suggests that there will be an increase of 30–50% in adverse respiratory health outcomes caused by dampness and mold exposure for those living in coastal and wetland areas. Fungal contamination in homes is associated with increased allergic rhinitis and asthma. Vector borne diseases increase as well due to the increase in still water after the floods have settled. The diseases that are vector borne are malaria, dengue, West Nile, and yellow fever. Floods have a huge impact on victims' psychosocial integrity. People suffer from a wide variety of losses and stress. One of the most treated illness in long-term health problems are depression caused by the flood and all the tragedy that flows with one.

Loss of life
Below is a list of the deadliest floods worldwide, showing events with death tolls at or above 100,000 individuals.

Positive impacts (benefits)
Floods (in particular more frequent or smaller floods) can also bring many benefits, such as recharging ground water, making soil more fertile and increasing nutrients in some soils. Flood waters provide much needed water resources in arid and semi-arid regions where precipitation can be very unevenly distributed throughout the year and kills pests in the farming land. Freshwater floods particularly play an important role in maintaining ecosystems in river corridors and are a key factor in maintaining floodplain biodiversity. Flooding can spread nutrients to lakes and rivers, which can lead to increased biomass and improved fisheries for a few years.

For some fish species, an inundated floodplain may form a highly suitable location for spawning with few predators and enhanced levels of nutrients or food. Fish, such as the weather fish, make use of floods in order to reach new habitats. Bird populations may also profit from the boost in food production caused by flooding.

Flooding can bring benefits, such as making the soil more fertile and providing it with more nutrients. For this reason, periodic flooding was essential to the well-being of ancient communities along the Tigris-Euphrates Rivers, the Nile River, the Indus River, the Ganges and the Yellow River among others.

The viability of hydropower, a renewable source of energy, is also higher in flood prone regions.

Flood control
In many countries around the world, waterways prone to floods are often carefully managed. Defenses such as detention basins, levees, bunds, reservoirs, and weirs are used to prevent waterways from overflowing their banks. When these defenses fail, emergency measures such as sandbags or portable inflatable tubes are often used to try to stem flooding. Coastal flooding has been addressed in portions of Europe and the Americas with coastal defenses, such as sea walls, beach nourishment, and barrier islands.

In the riparian zone near rivers and streams, erosion control measures can be taken to try to slow down or reverse the natural forces that cause many waterways to meander over long periods of time. Flood controls, such as dams, can be built and maintained over time to try to reduce the occurrence and severity of floods as well. In the United States, the U.S. Army Corps of Engineers maintains a network of such flood control dams.

In areas prone to urban flooding, one solution is the repair and expansion of human-made sewer systems and stormwater infrastructure. Another strategy is to reduce impervious surfaces in streets, parking lots and buildings through natural drainage channels, porous paving, and wetlands (collectively known as green infrastructure or sustainable urban drainage systems (SUDS)). Areas identified as flood-prone can be converted into parks and playgrounds that can tolerate occasional flooding. Ordinances can be adopted to require developers to retain stormwater on site and require buildings to be elevated, protected by floodwalls and levees, or designed to withstand temporary inundation. Property owners can also invest in solutions themselves, such as re-landscaping their property to take the flow of water away from their building and installing rain barrels, sump pumps, and check valves.

In some areas, the presence of certain species (such as beavers) can be beneficial for flood control reasons. Beavers build and maintain beaver dams which will reduce the height of flood waves moving down the river (during periods of heavy rains), and will reduce or eliminate damage to human structures, at the cost of minor flooding near the dams (often on farmland). Besides this, they also boost wildlife populations and filter pollutants (manure, fertilisers, slurry). UK environment minister Rebecca Pow stated that in the future the beavers could be considered a "public good" and landowners would be paid to have them on their land.

Flood safety planning
In the United States, the National Weather Service gives out the advice "Turn Around, Don't Drown" for floods; that is, it recommends that people get out of the area of a flood, rather than trying to cross it. At the most basic level, the best defense against floods is to seek higher ground for high-value uses while balancing the foreseeable risks with the benefits of occupying flood hazard zones. Critical community-safety facilities, such as hospitals, emergency-operations centers, and police, fire, and rescue services, should be built in areas least at risk of flooding. Structures, such as bridges, that must unavoidably be in flood hazard areas should be designed to withstand flooding. Areas most at risk for flooding could be put to valuable uses that could be abandoned temporarily as people retreat to safer areas when a flood is imminent.

Planning for flood safety involves many aspects of analysis and engineering, including:
 * observation of previous and present flood heights and inundated areas,
 * statistical, hydrologic, and hydraulic model analyses,
 * mapping inundated areas and flood heights for future flood scenarios,
 * long-term land use planning and regulation,
 * engineering design and construction of structures to control or withstand flooding,
 * intermediate-term monitoring, forecasting, and emergency-response planning, and
 * short-term monitoring, warning, and response operations.

Each topic presents distinct yet related questions with varying scope and scale in time, space, and the people involved. Attempts to understand and manage the mechanisms at work in floodplains have been made for at least six millennia.

In the United States, the Association of State Floodplain Managers works to promote education, policies, and activities that mitigate current and future losses, costs, and human suffering caused by flooding and to protect the natural and beneficial functions of floodplains – all without causing adverse impacts. A portfolio of best practice examples for disaster mitigation in the United States is available from the Federal Emergency Management Agency.

Flood clean-up safety
Clean-up activities following floods often pose hazards to workers and volunteers involved in the effort. Potential dangers include electrical hazards, carbon monoxide exposure, musculoskeletal hazards, heat or cold stress, motor vehicle-related dangers, fire, drowning, and exposure to hazardous materials. Because flooded disaster sites are unstable, clean-up workers might encounter sharp jagged debris, biological hazards in the flood water, exposed electrical lines, blood or other body fluids, and animal and human remains. In planning for and reacting to flood disasters, managers provide workers with hard hats, goggles, heavy work gloves, life jackets, and watertight boots with steel toes and insoles.

Mathematical models and computer tools
A series of annual maximum flow rates in a stream reach can be analyzed statistically to estimate the 100-year flood and floods of other recurrence intervals there. Similar estimates from many sites in a hydrologically similar region can be related to measurable characteristics of each drainage basin to allow indirect estimation of flood recurrence intervals for stream reaches without sufficient data for direct analysis.

Physical process models of channel reaches are generally well understood and will calculate the depth and area of inundation for given channel conditions and a specified flow rate, such as for use in floodplain mapping and flood insurance. Conversely, given the observed inundation area of a recent flood and the channel conditions, a model can calculate the flow rate. Applied to various potential channel configurations and flow rates, a reach model can contribute to selecting an optimum design for a modified channel. Various reach models are available as of 2015, either 1D models (flood levels measured in the channel) or 2D models (variable flood depths measured across the extent of a floodplain). HEC-RAS, the Hydraulic Engineering Center model, is among the most popular software, if only because it is available free of charge. Other models such as TUFLOW combine 1D and 2D components to derive flood depths across both river channels and the entire floodplain.

Physical process models of complete drainage basins are even more complex. Although many processes are well understood at a point or for a small area, others are poorly understood at all scales, and process interactions under normal or extreme climatic conditions may be unknown. Basin models typically combine land-surface process components (to estimate how much rainfall or snowmelt reaches a channel) with a series of reach models. For example, a basin model can calculate the runoff hydrograph that might result from a 100-year storm, although the recurrence interval of a storm is rarely equal to that of the associated flood. Basin models are commonly used in flood forecasting and warning, as well as in analysis of the effects of land use change and climate change.

In the United States, an integrated approach to real-time hydrologic computer modelling uses observed data from the U.S. Geological Survey (USGS), various cooperative observing networks, various automated weather sensors, the NOAA National Operational Hydrologic Remote Sensing Center (NOHRSC), various hydroelectric companies, etc. combined with quantitative precipitation forecasts (QPF) of expected rainfall and/or snow melt to generate daily or as-needed hydrologic forecasts. The NWS also cooperates with Environment Canada on hydrologic forecasts that affect both the US and Canada, like in the area of the Saint Lawrence Seaway.

The Global Flood Monitoring System, "GFMS", a computer tool which maps flood conditions worldwide, is available online. Users anywhere in the world can use GFMS to determine when floods may occur in their area. GFMS uses precipitation data from NASA's Earth observing satellites and the Global Precipitation Measurement satellite, "GPM". Rainfall data from GPM is combined with a land surface model that incorporates vegetation cover, soil type, and terrain to determine how much water is soaking into the ground, and how much water is flowing into streamflow.

Users can view statistics for rainfall, streamflow, water depth, and flooding every 3 hours, at each 12-kilometer gridpoint on a global map. Forecasts for these parameters are 5 days into the future. Users can zoom in to see inundation maps (areas estimated to be covered with water) in 1-kilometer resolution.

Flood forecasts and warnings
Anticipating floods before they occur allows for precautions to be taken and people to be warned so that they can be prepared in advance for flooding conditions. For example, farmers can remove animals from low-lying areas and utility services can put in place emergency provisions to re-route services if needed. Emergency services can also make provisions to have enough resources available ahead of time to respond to emergencies as they occur. People can evacuate areas to be flooded.

In order to make the most accurate flood forecasts for waterways, it is best to have a long time-series of historical data that relates stream flows to measured past rainfall events. Coupling this historical information with real-time knowledge about volumetric capacity in catchment areas, such as spare capacity in reservoirs, ground-water levels, and the degree of saturation of area aquifers is also needed in order to make the most accurate flood forecasts.

Radar estimates of rainfall and general weather forecasting techniques are also important components of good flood forecasting. In areas where good quality data is available, the intensity and height of a flood can be predicted with fairly good accuracy and plenty of lead time. The output of a flood forecast is typically a maximum expected water level and the likely time of its arrival at key locations along a waterway, and it also may allow for the computation of the likely statistical return period of a flood. In many developed countries, urban areas at risk of flooding are protected against a 100-year flood – that is a flood that has a probability of around 63% of occurring in any 100-year period of time.

According to the U.S. National Weather Service (NWS) Northeast River Forecast Center (RFC) in Taunton, Massachusetts, a rule of thumb for flood forecasting in urban areas is that it takes at least 1 in of rainfall in around an hour's time in order to start significant ponding of water on impermeable surfaces. Many NWS RFCs routinely issue Flash Flood Guidance and Headwater Guidance, which indicate the general amount of rainfall that would need to fall in a short period of time in order to cause flash flooding or flooding on larger water basins.

Etymology
The word "flood" comes from the Old English flōd, a word common to Germanic languages (compare German Flut, Dutch vloed from the same root as is seen in flow, float; also compare with Latin fluctus, flumen), meaning "a flowing of water, tide, an overflowing of land by water, a deluge, Noah's Flood; mass of water, river, sea, wave,". The Old English word flōd comes from the Proto-Germanic floduz (Old Frisian flod, Old Norse floð, Middle Dutch vloet, Dutch vloed, German Flut, and Gothic flodus derives from floduz).

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Goose

A goose (: geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera Anser (grey geese and white geese) and Branta (black geese). Some members of the Tadorninae subfamily (e.g., Egyptian goose, Orinoco goose) are commonly called geese, but are not considered "true geese" taxonomically. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are smaller.

The term "goose" may refer to such bird of either sex, but when paired with "gander", refers specifically to a female one (the latter referring to a male). Young birds before fledging are called goslings. The collective noun for a group of geese on the ground is a gaggle; when in flight, they are called a skein, a team, or a wedge; when flying close together, they are called a plump.

Etymology
The word "goose" is a direct descendant of Proto-Indo-European *ǵʰh₂éns. In Germanic languages, the root gave Old English gōs with the plural gēs and gandra (becoming Modern English goose, geese, gander, respectively), West Frisian goes, gies and guoske, gans, New High German Gans, Gänse, and Ganter, and Old Norse gās and gæslingr, whence English gosling.

This term also gave žąsìs, gé (goose, from Old Irish géiss), Hindi: कलहंस, anser, Spanish and ganso, Ancient χήν (khēn), gatë (swans), hanhi, Avestan zāō, gęś, gâscă / gânsac, гуска / гусак (huska / husak), гусыня / гусь (gusyna / gus), husa, and  (ghāz).

True geese and their relatives

The two living genera of true geese are: Anser, grey geese and white geese, such as the greylag goose and snow goose, and Branta, black geese, such as the Canada goose.

Two genera of geese are only tentatively placed in the Anserinae; they may belong to the shelducks or form a subfamily on their own: Cereopsis, the Cape Barren goose, and Cnemiornis, the prehistoric New Zealand goose. Either these or, more probably, the goose-like coscoroba swan is the closest living relative of the true geese.

Fossils of true geese are hard to assign to genus; all that can be said is that their fossil record, particularly in North America, is dense and comprehensively documents many different species of true geese that have been around since about 10 million years ago in the Miocene. The aptly named Anser atavus (meaning "progenitor goose") from some 12 million years ago had even more plesiomorphies in common with swans. In addition, some goose-like birds are known from subfossil remains found on the Hawaiian Islands.

Geese are monogamous, living in permanent pairs throughout the year; however, unlike most other permanently monogamous animals, they are territorial only during the short nesting season. Paired geese are more dominant and feed more, two factors that result in more young.

Fossil record
Goose fossils have been found ranging from 10 to 12 million years ago (Middle Miocene). Garganornis ballmanni from Late Miocene (~ 6-9 Ma) of Gargano region of central Italy, stood one and a half meters tall and weighed about 22 kilograms. The evidence suggests the bird was flightless, unlike modern geese.

Migratory patterns
Most goose species are migratory, though populations of Canada geese living near human developments may remain in a locality year-round. These 'resident' geese, found primarily in the eastern United States, may migrate only short distances, or not at all, if they have adequate food supply and access to open water.

Navigation
Migratory geese may use several environmental cues in timing the beginning of their migration, including temperature, predation threat, and food availability. Like all migratory birds, geese exhibit an ability to navigate using an internal compass, using a combination of innate and learned behaviors. The preferred direction of migration is heritable, and birds appear to orient themselves using Earth's magnetic field. Migrations occur over the course of several weeks, and up to 85% of migration time is spent at perennial stopover sites, where individuals rest and build up fat stores for further travel.

Formation
Geese, like other birds, fly in a V formation. This formation helps to conserve energy in flight, and aids in communication and monitoring of flock mates. Using great white pelicans as a model species, researchers showed that flying in a V formation increased the aerodynamics of trailing birds, thus requiring fewer wing flaps to stay aloft and lowering individuals' heartrates. Leading geese switch positions on longer flights to allow for multiple individuals to gain benefits from the less energy-intensive trailing positions; in family groups, parental birds almost always lead.

Other birds called "geese"
Some mainly Southern Hemisphere birds are called "geese", most of which belong to the shelduck subfamily Tadorninae. These are:
 * The Orinoco goose (Neochen jubata)
 * The Egyptian goose (Alopochen aegyptiaca)
 * The South American sheldgeese in the genus Chloephaga
 * The prehistoric Malagasy sheldgoose (Centrornis majori)

Others:
 * The spur-winged goose (Plectropterus gambensis) is most closely related to the shelducks, but distinct enough to warrant its own subfamily, the Plectropterinae.
 * The blue-winged goose (Cyanochen cyanopterus) and the Cape Barren goose (Cereopsis novaehollandiae) have disputed affinities. They belong to separate ancient lineages that may ally either to the Tadorninae, the Anserinae, or closer to the dabbling ducks (Anatinae).
 * The three species of small waterfowl in the genus Nettapus named "pygmy geese"; they seem to represent another ancient lineage, with possible affinities to the Cape Barren goose or the spur-winged goose.
 * The maned goose, also known as the maned duck or Australian wood duck (Chenonetta jubata)
 * A genus of prehistorically extinct seaducks, Chendytes, is sometimes called the "diving-geese" due to their large size.
 * The magpie goose (Anseranas semipalmata) is the only living species in the family Anseranatidae.
 * The northern gannet (Morus bassanus), a seabird, is also known as the "solan goose", although it is unrelated to the true geese, or any other Anseriformes for that matter.

Sayings and phrases that reference geese

 * To "have a gander" is to look at something.
 * "What's good sauce for the goose is good sauce for the gander" or "What's good for the goose is good for the gander" means that what is an appropriate treatment for one person is equally appropriate for someone else. This statement supporting equality is frequently used in the context of sex and gender, because a goose is female and a gander is male.
 * Saying that someone's "goose is cooked" means that they are about to be punished.
 * The common phrase "silly goose" is used when referring to someone who is acting particularly silly.
 * "Killing the goose that lays the golden eggs", derived from Aesop's Fables, is a saying referring to a greed-motivated action that destroys or otherwise renders useless a favourable situation that would have provided benefits over time.
 * "A wild goose chase" is a useless, futile waste of time and effort. It is derived from a 16th-century horse racing event.
 * A raised, rounded area of swelling (typically a hematoma) caused by an impact injury is sometimes metaphorically called a "goose egg", especially if it occurs on the head.

Geese as characters in cultural works

 * Mother Goose is a fictitious children's storybook author associated with several collections of fairy tales and nursery rhymes translated into English during the 18th century.
 * Gänsewein (German, lit. 'Goose wine' ) is a playful term for plain drinking water, first documented the Podagrammisch Trostbüchlein by Johann Fischart (1577).
 * Popular indie game Untitled Goose Game released in 2019 chronicles the activities of an ornery goose in an English village.
 * In the late 18th century poem, The Goose and the Common, geese serve to illustrate the social and economic issues cased by the enclosure of common land.

"Gray Goose Laws" in Iceland
The oldest collection of Medieval Icelandic laws is known as "Grágás"; i.e., the Gray Goose Laws. Various etymologies were offered for that name:
 * The fact that the laws were written with a goose quill;
 * The fact that the laws were bound in goose skin;
 * Because of the age of the laws — it was then believed that geese lived longer than other birds.

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Debugger

A debugger or debugging tool is a computer program used to test and debug other programs (the "target" program). The main use of a debugger is to run the target program under controlled conditions that permit the programmer to track its execution and monitor changes in computer resources that may indicate malfunctioning code. Typical debugging facilities include the ability to run or halt the target program at specific points, display the contents of memory, CPU registers or storage devices (such as disk drives), and modify memory or register contents in order to enter selected test data that might be a cause of faulty program execution.

The code to be examined might alternatively be running on an instruction set simulator (ISS), a technique that allows great power in its ability to halt when specific conditions are encountered, but which will typically be somewhat slower than executing the code directly on the appropriate (or the same) processor. Some debuggers offer two modes of operation, full or partial simulation, to limit this impact.

A "trap" occurs when the program cannot normally continue because of a programming bug or invalid data. For example, the program might have tried to use an instruction not available on the current version of the CPU or attempted to access unavailable or protected memory. When the program "traps" or reaches a preset condition, the debugger typically shows the location in the original code if it is a source-level debugger or symbolic debugger, commonly now seen in integrated development environments. If it is a low-level debugger or a machine-language debugger it shows the line in the disassembly (unless it also has online access to the original source code and can display the appropriate section of code from the assembly or compilation).

Features
Typically, debuggers offer a query processor, a symbol resolver, an expression interpreter, and a debug support interface at its top level. Debuggers also offer more sophisticated functions such as running a program step by step (single-stepping or program animation), stopping (breaking) (pausing the program to examine the current state) at some event or specified instruction by means of a breakpoint, and tracking the values of variables. Some debuggers have the ability to modify the program state while it is running. It may also be possible to continue execution at a different location in the program to bypass a crash or logical error.

The same functionality which makes a debugger useful for correcting bugs allows it to be used as a software cracking tool to evade copy protection, digital rights management, and other software protection features. It often also makes it useful as a general verification tool, fault coverage, and performance analyzer, especially if instruction path lengths are shown. Early microcomputers with disk-based storage often benefitted from the ability to diagnose and recover corrupted directory or registry data records, to "undelete" files marked as deleted, or to crack file password protection.

Most mainstream debugging engines, such as gdb and dbx, provide console-based command line interfaces. Debugger front-ends are popular extensions to debugger engines that provide IDE integration, program animation, and visualization features.

Record and replay debugging
Record and replay debugging, also known as "software flight recording" or "program execution recording", captures application state changes and stores them to disk as each instruction in a program executes. The recording can then be replayed over and over, and interactively debugged to diagnose and resolve defects. Record and replay debugging is very useful for remote debugging and for resolving intermittent, non-deterministic, and other hard-to-reproduce defects.

Reverse debugging
Some debuggers include a feature called "reverse debugging", also known as "historical debugging" or "backwards debugging". These debuggers make it possible to step a program's execution backwards in time. Various debuggers include this feature. Microsoft Visual Studio (2010 Ultimate edition, 2012 Ultimate, 2013 Ultimate, and 2015 Enterprise edition) offers IntelliTrace reverse debugging for C#, Visual Basic .NET, and some other languages, but not C++. Reverse debuggers also exist for C, C++, Java, Python, Perl, and other languages. Some are open source; some are proprietary commercial software. Some reverse debuggers slow down the target by orders of magnitude, but the best reverse debuggers cause a slowdown of 2× or less. Reverse debugging is very useful for certain types of problems, but is still not commonly used yet.

Time Travel debugging
In addition to the features of reverse debuggers, time travel debugging also allow users to interact with the program, changing the history if desired, and watch how the program responds.

Language dependency
Some debuggers operate on a single specific language while others can handle multiple languages transparently. For example, if the main target program is written in COBOL but calls assembly language subroutines and PL/1 subroutines, the debugger may have to dynamically switch modes to accommodate the changes in language as they occur.

Memory protection
Some debuggers also incorporate memory protection to avoid storage violations such as buffer overflow. This may be extremely important in transaction processing environments where memory is dynamically allocated from memory 'pools' on a task by task basis.

Hardware support for debugging
Most modern microprocessors have at least one of these features in their CPU design to make debugging easier:
 * Hardware support for single-stepping a program, such as the trap flag.
 * An instruction set that meets the Popek and Goldberg virtualization requirements makes it easier to write debugger software that runs on the same CPU as the software being debugged; such a CPU can execute the inner loops of the program under test at full speed, and still remain under debugger control.
 * In-system programming allows an external hardware debugger to reprogram a system under test (for example, adding or removing instruction breakpoints). Many systems with such ISP support also have other hardware debug support.
 * Hardware support for code and data breakpoints, such as address comparators and data value comparators or, with considerably more work involved, page fault hardware.
 * JTAG access to hardware debug interfaces such as those on ARM architecture processors or using the Nexus command set. Processors used in embedded systems typically have extensive JTAG debug support.
 * Micro controllers with as few as six pins need to use low pin-count substitutes for JTAG, such as BDM, Spy-Bi-Wire, or debugWIRE on the Atmel AVR. DebugWIRE, for example, uses bidirectional signaling on the RESET pin.

Debugger front-ends
Some of the most capable and popular debuggers implement only a simple command line interface (CLI)—often to maximize portability and minimize resource consumption. Developers typically consider debugging via a graphical user interface (GUI) easier and more productive. This is the reason for visual front-ends, that allow users to monitor and control subservient CLI-only debuggers via graphical user interface. Some GUI debugger front-ends are designed to be compatible with a variety of CLI-only debuggers, while others are targeted at one specific debugger.

List of debuggers
Some widely used debuggers are:
 * Arm DTT, formerly known as Allinea DDT
 * Eclipse debugger API used in a range of IDEs: Eclipse IDE (Java), Nodeclipse (JavaScript)
 * Firefox JavaScript debugger
 * GDB - the GNU debugger
 * LLDB
 * Microsoft Visual Studio Debugger
 * Radare2
 * Valgrind
 * WinDbg

Earlier minicomputer debuggers include:
 * Dynamic debugging technique (DDT)
 * On-line Debugging Tool (ODT)

Mainframe debuggers include:
 * CA/EZTEST

title: Debugger