What You Need to Know About Floods

Flooding causes more damage in the United States than any other severe weather related event, an average of $4.6 billion a year in the past 20 years (1984-2003). Flooding can occur in any of the 50 states or U.S. territories at anytime of the year.

Flash Flood Terminology:

Flash Flood Watch: Indicates that flash flooding is a possibility in or close to the watch area. Those in the affected area are urged to be ready to take action if a flash flood warning is issued or flooding is observed. These watches are issued for flooding that is expected to occur within 6 hours after the heavy rains have ended.

Flash Flood Warning: A flood warning issued for life/property threatening flooding that will occur within 6 hours. It could be issued for rural or urban areas as well as for areas along the major rivers. Very heavy rain in a short period of time can lead to flash flooding, depending on local terrain, ground cover, degree of urbanization, amount of man-made changes to the natural river banks, and initial ground or river conditions. Dam breaks or ice jams can also create flash flooding.

Flash Flood Statement: A Flash Flood Statement is issued to inform the public about current flash flood conditions. These statements usually contain river stage information if major streams or rivers are involved.

Urban/Small Stream Flood Advisory: Alerts the public to flooding, which is generally only an inconvenience (not life-threatening) to those living in the affected area. Issued when heavy rain will cause flooding of streets and low-lying places in urban areas. Also used if small rural or urban streams are expected to reach or exceed bankfull. Some damage to homes or roads could occur.

Flash floods can strike any time and any place with little or no warning. In mountainous or flat terrain, distant rain may be channeled into gullies and ravines, turning a quiet streamside campsite or wash into a rampaging torrent in minutes. City streets can become rivers in seconds. Observe these flash flood safety rules. They could save your life.