Drought, condition of abnormally dry weather within a geographic region where some rain might usually be expected. A drought is thus quite different from a dry climate which designates a region that is normally, or at least seasonally, dry. Athough the quantity of the worlds freshwater resourses is more than adeguate to meet human needs, but uneven distribution from place to place can result in serious droughts. The word drought is applied to a time where an unusual shortage of rain causes a serious hydrological imbalance: Water-supply reservoirs are empty, wells dry up, and crop damage ensues. The severity of the drought is determened by the degree of moisture deficiency, its lengh, and the size of the area