Flash flooding is a result of heavy localized rainfall such as that from slow moving intense thunderstorms. Flash floods often result from small creeks and streams overflowing during heavy rainfall. These floods often become raging torrents of water which rip through river beds, city streets, coastal sections and valleys or canyons, sweeping everything with them. Flash Flooding usually occurs within 6 hours of a heavy rain event. These floods occur seasonally with general rains or torrential rains associated with tropical storms, that later drain in river basins and fill them with an over- abundance of water.
General flooding occurs in urban areas and areas with poor drainage after heavy rain.
In hilly terrain, flash floods can strike with little or no advance warning. Distant rain may be channeled into gullies and ravines, turning a quiet stream into a rampaging torrent in minutes. Never camp on low ground next to streams since a flash flood can catch you while you're asleep. Even if it looks shallow enough to cross. The large majority of deaths due to flash flooding occur with people driving through flooded areas.