History: Dust Bowl, Dirty Thirties, 1930s, Great Plains, American And Canadian Prairies

When severe drought struck the Great Plains region in the 1930s, it exposed the increased risk for erosion that was created by the farming practices in use at the time. The drought dried the topsoil and over time it became friable, reduced to a powdery consistency in some places. Without the indigenous grasses in place, the high winds that commonly occur on the plains were able to create the massive dust storms that marked the Dust Bowl period.
Geographic characteristics
The Dust Bowl area lies principally west of the 100th meridian on the High Plains, characterized by plains which vary from rolling in the north to flat in the Llano Estacado. Elevation ranges from 2,500 feet (760 m) in the east to 6,000 feet (1,800 m) at the base of the Rocky Mountains. The area is semiarid, receiving less than 20 inches (510 mm) of rain annually; this rainfall supports the shortgrass prairie biome originally present in the area. The region is also prone to extended drought, alternating with unusual wetness of equivalent duration. During wet years, the rich soil provides bountiful agricultural output, but crops fail during dry years. The region is also subject to high winds.