Nationally, flash floods are responsible for more deaths than any other weather phenomena. Flash flooding is usually a result of sudden, very heavy rain that occurs in a localized area, which may cause small innocent streams to turn violent. During flash floods, these streams become raging torrents of water that are capable of causing tremendous amounts of damage. This is why they are often called "The Awesome Power!".
The closest major flash flood to the Tri-State area occurred in Rapid City on June 9, 1972. Many times in the spring we experience floods as rivers and streams swell above their banks due to melting snow or heavy rain. The difference between floods and flash floods is the time of onset. Flash floods happen much quicker.
Many Flash Floods occur at night, so be prepared to take quick action!!