Question: what were the two causes of the dust bowl?
Answer: severe drought

The Dust Bowl, also known as the Dirty Thirties, 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 wind erosion (the Aeolian processes) 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. With insufficient understanding of the ecology of the plains, farmers had conducted extensive deep plowing of the virgin topsoil of the Great