Title: Oklahoma
Content:  Ku Klux Klan had declined to negligible influence within the state. During the 1930s, parts of the state began suffering the consequences of poor farming practices. This period was known as the Dust Bowl, throughout which areas of Kansas, Texas, New Mexico and northwestern Oklahoma were hampered by long periods of little rainfall, strong winds, abnormally high temperatures, and most notably, severe dust storms sending thousands of farmers into poverty and forcing them to relocate to more fertile areas of the western United States. Over a twenty-year period ending in 1950, the state saw its only historical decline in population, dropping 6.9 percent 
Title: History of Oklahoma
Content:  Short-term drought and long-term poor agricultural practices led to the Dust Bowl when massive dust storms blew away the soil from large tracts of arable land and deposited it on nearby farms or even far-distant locations. The resulting crop failures forced many small farmers to flee the state altogether. Although the most persistent dust storms primarily affected the Panhandle, much of the state experienced occasional dusters, intermittent severe drought, and occasional searing heat. Towns such as Alva, Altus, and Poteau each recorded temperatures of 120 °F (49 °C) during the epic summer of 1936.
Title: Oklahoma Panhandle
Content:  The Panhandle was severely affected by the drought of the 1930s. The drought began in 1932 and created massive dust storms. By 1935, the area was widely known as the Dust Bowl. The dust storms were largely a result of poor farming techniques and the plowing up of the native grasses that had held the fine soil in place. Despite government efforts to implement conservation measures and change the basic farming methods of the region, the Dust Bowl persisted for nearly a decade. It contributed significantly to the length of the Great Depression in the United States. Each of the three counties experienced a major loss of population during the 1930s.
Title: Droughts in the United States
Content:  At times the clouds blackened the sky reaching all the way to East Coast cities such as New York and Washington, D.C. Much of the soil ended up deposited in the Atlantic Ocean, carried by prevailing winds which were in part created by the dry and bare soil conditions itself. These immense dust storms—given names such as "Black Blizzards" and "Black Rollers"—often reduced visibility to a few feet (around a meter). The Dust Bowl affected 100000000 acre, centered on the panhandles of Texas and Oklahoma, and adjacent parts of New Mexico, Colorado, and Kansas. Millions of acres of farmland became useless, and hundreds of thousands of people were forced to leave their homes; many of these families (often known as "Okies", since so 
Title: Dust Bowl
Content:   The Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s; severe drought and a failure to apply dryland farming methods to prevent the aeolian processes (wind erosion) caused the phenomenon. The drought came in three waves: 1934, 1936, and 1939–1940, but some regions of the High Plains experienced drought conditions for as many as eight years. The Dust Bowl has been the subject of many cultural works, notably the novel The Grapes of Wrath (1939) by John Steinbeck, the folk music of Woody Guthrie, and photographs depicting the conditions of migrants by Dorothea Lange, particularly the Migrant Mother.
Title: Dunlap, Kansas
Content:  occurred. The Dust Bowl was caused by poor farming techniques and resulted in dust storms across the country. This resulted in difficulties in growing crops. All these factors lead to the abandonment of small farming communities across the country, resulting in the ghost town. The last celebration of Juneteenth, a celebration of the day slaves heard they were emancipated, was in 1931. Eventually, the bank filed for bankruptcy and businesses closed. This was then followed by the school and then the church closing its doors, even the old Methodist church which was donated to the Kansas Historical Society. And just as fast as the population 
Title: Black Sunday (storm)
Content:   Black Sunday refers to a particularly severe dust storm that occurred on April 14, 1935 as part of the Dust Bowl in the United States. It was one of the worst dust storms in American history and it caused immense economic and agricultural damage. It is estimated to have displaced 300 thousand tons of topsoil from the prairie area. On the afternoon of April 14, residents of several plains states were forced to take cover as a dust storm or "black blizzard" blew through the region. The storm hit the Oklahoma panhandle and northwestern Oklahoma first, and moved south for the remainder of the day. It hit Beaver, Oklahoma around 4 p.m., Boise City around 5:15, and Amarillo, Texas at 7:20. The conditions were the most severe in the Oklahoma and Texas panhandles, but the storm's effects were also felt in other surrounding areas. The combination of drought, erosion, bare soil, and winds caused the dust to fly freely and at high speeds.
Title: Dust Bowl
Content:  rewriting Geiger's news story. While the term "the Dust Bowl" was originally a reference to the geographical area affected by the dust, today it usually refers to the event itself (the term "Dirty Thirties" is also sometimes used). The drought and erosion of the Dust Bowl affected 100000000 acre that centered on the panhandles of Texas and Oklahoma and touched adjacent sections of New Mexico, Colorado, and Kansas. The Dust Bowl forced tens of thousands of poverty-stricken families, who were unable to pay mortgages or grow crops, to abandon their farms, and losses reached $25 million per day by 1936. Many 
Title: History of the United States (1918–1945)
Content:  to erode, and combined with the weather conditions (the 1930s was the overall warmest decade of the 20th century in North America) caused an ecological disaster. The dry soil was lifted by wind and blown into huge dust storms that blanketed entire towns, a phenomenon that continued for several years. Those who had lost their homes and livelihoods in the Dust Bowl were lured westward by advertisements for work put out by agribusiness in western states, such as California. The migrants came to be called Okies, Arkies, and other derogatory names as they flooded the labor supply of the agricultural fields, driving down wages, pitting desperate 
Title: Oklahoma
Content:  impoverished families migrated out of the state after the Dust Bowl. Soil and water conservation projects markedly changed practices in the state and led to the construction of massive flood control systems and dams; they built hundreds of reservoirs and man-made lakes to supply water for domestic needs and agricultural irrigation. By the 1960s, Oklahoma had created more than 200 lakes, the most in the nation. In 1995, Oklahoma City was the site of one of the most destructive act of domestic terrorism in American history. The Oklahoma City bombing of April 19, 1995, in which Timothy McVeigh detonated a large, crude explosive 

Question: when did the dust bowl end in oklahoma?
Answer: 1940.