The term "Dust Bowl" is used to refer to a huge area of the American Midwest that experienced a terrible drought during the Great Depression. The drought led to a situation in which huge dust storms arose. This gave the Dust Bowl its name.
The drought arose in 1931 and continued until 1939. It prevented crops from growing in fast enough to hold the soil when high winds came to the region as they tend to do quite often. This led to the huge dust storms. These storms affected a tremendous area of land, largely in Kansas, Oklahoma, Texas, New Mexico, and Colorado. They forced thousands of people off their land (which many had lost when they could no longer pay their debts). These people became the "Okies" who traveled west in search of some way to make a living.