A flood is an overflow of water that submerges land which is usually dry. The European Union (EU) Floods Directive defines a flood as a covering by water of land not normally covered by water. In the sense of “flowing water”, the word may also be applied to the inflow of the tide.
Floods are one of the most common hazards in the United States. A flood occurs any time a body of water rises to cover what is usually dry land. Flood effects can be local, impacting a neighborhood or community, or very large, affecting entire river basins and multiple states. While some floods develop slowly, over a period of days; some may develop quickly, and cause flash floods. Floods are the most frequent and costly natural disasters in terms of human hardship and economic loss.
“Rule number one” is to move quickly to higher ground. Flood waters can carry debris, scour soil and asphalt, and trigger landslides. Even shallow-depth, fast-moving flood waters of 24 inches can produce enough force to carry away a vehicle, and six inches of swiftly moving water can knock someone off his or her feet. Never try to walk, swim, or drive through flood waters!
The risk of flood will be reported by radio and television, as well as NOAA Weather Radio using EAS (Emergency Alert System), as soon as the National Weather Service (NWS) issues a flood or flash flood watch or warning.