Impacts of Flash Floods

Abstract

Floods can be classified in four types based on characteristics of the flood event: flash floods of a few hours duration; single-event floods of longer duration; multiple-event floods; and seasonal floods. Flash floods most frequently occur on small headwater basins in association with short-duration convective, frontal, or orographic type storms with high-intensity rain cells. The economic, social, and environmental effects of flash floods are similar to impacts of “river floods” of other types; the major differences being that the effects of flash floods generally occur with little, if any, warning over a very short time period and are generally limited to relatively small areas. However, the effects of flash floods are often catastrophic and may, depending on development and land use in the affected basins, result in large loss of life because of the sudden onset of the flood events.