Dust Bowl refers to a series of destructive wind and dust storms that struck the United States during the 1930's. These storms ranked among the worst environmental disasters in world history. Most of the damage occurred from 1935 to 1938 in the southern Great Plains, and so this area also became known as the Dust Bowl. Altogether, the storms damaged about 50 million acres (20 million hectares) of land, mainly in Colorado, Kansas, New Mexico, Oklahoma, and Texas. An additional 50 million acres were endangered before conservation measures began to take effect.