| A flash flood (also a freshet) is a rapid flooding of low-lying areas, rivers and streams that is caused by the intense rainfall associated with a thunderstorm, or multiple training thunderstorms. Flash flooding occurs when the ground under a storm becomes saturated with water so quickly that it cannot be absorbed. The runoff collects in low-lying areas and flows rapidly downhill. As a result, anything in its path is suddenly in rising water. These most often occur in dry areas that have recently received precipitation, but the flash flood can flow for a long distance as long as there is a path downhill. |