Dust Bowl

A name given, early in 1935, to the region in the south-central United States affected by drought and duststorms at that time.

It included parts of five states: Colorado, Kansas, New Mexico, Texas, and Oklahoma. It resulted from a long period of deficient rainfall combined with loosening of the soil by destruction of the natural vegetation. The name has since been extended to similar regions in other parts of the world.

Any function of time f(t) is periodic with period t if f(t) = f(t + τ) for all times t, where τ is the smallest number for which this equality holds.