title: Dust Bowl
context: 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.[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 many as eight years.[3] With insufficient understanding of the ecology of the plains, farmers had conducted extensive deep plowing of the virgin topsoil of the Great Plains during the previous decade; this had displaced the native, deep-rooted grasses that normally trapped soil and moisture even during periods of drought and high winds.  The rapid mechanization of farm equipment, especially small gasoline tractors, and widespread use of the combine harvester contributed to farmers' decisions to convert arid grassland (much of which received no more than 10inches (~250mm) of precipitation per year) to cultivated cropland.[4]
question: What caused the Dust Bowl?
answers: severe drought and a failure to apply dryland farming methods to prevent  the aeolian processes (wind erosion)