Flash floods are a fast moving type of flood. They happen after very heavy rain and that rain collects in a gully or stream, turning an often serene spot into a quick flowing current. This quick change catches people off guard which claims so many lives. All floods include a rise in the water level. The difference between a flash flood and a normal flood is that flash floods move quickly across the land with little warning. They have the ability to move boulders, tear out trees and demolish bridges and buildings. Flash floods can also be when a dam breaks and a great quantity of water is released, destroying everything in its path.