Dust Bowl
The Dust Bowl was a period of severe dust storms that greatly damaged the agriculture and ecology of the American and Canadian prairies during the 1930s. The phenomenon was caused by a combination of natural factors, including severe drought, and human behavior, including the destruction of natural topsoil by settlers who did not use dryland farming methods to prevent wind erosion. 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. It exacerbated an already existing agricultural recession.
Read on Wikipedia