The Dust Bowl was the result of a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s. The phenomenon was caused by a combination of natural factors (severe drought) and human-made factors: a failure to apply dryland farming methods to prevent wind erosion, most notably the destruction of the natural topsoil by settlers in the region.[1][2] The drought came in three waves: 1934, 1936, and 1939–1940, but some regions of the High Plains experienced drought conditions for as long as eight years.[3]
The Dust Bowl has been the subject of many cultural works, including John Steinbeck's 1939 novel The Grapes of Wrath, the folk music of Woody Guthrie, and Dorothea Lange's photographs depicting the conditions of migrants, particularly Migrant Mother, taken in 1936.
whatwelearned
was invoked but never defined (see the help page).