Skip Navigation Linkwww.nws.noaa.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
NWS Hydrologic Service Program
   

Flood Safety


Commonly Asked Questions

Q: Is flooding really that big of a deal?

Flooding causes more damage in the United States than any other severe weather related event, an average of $5 billion a year. Flooding can occur in any of the 50 states or U.S. territories at anytime of the year.

Q: How can I find out if I am in danger from a flood?

NOAA Weather Radio All Hazards is one of the best ways to receive warnings from the National Weather Service. NOAA Weather Radio All Hazards is a nationwide network of radio stations broadcasting continuous weather and river information direct from nearby NWS offices. Also, the NWS web page provides forecasts and warning and identifies where flooding is occurring (www.weather.gov/water).

Q: How do I know how severe a flood will be?

Once a river reaches flood stage, the flood severity categories used by the NWS include minor flooding, moderate flooding, and major flooding. Each category has a definition based on property damage and public threat.

  • Minor Flooding - minimal or no property damage, but possibly some public threat or inconvenience
  • Moderate Flooding - some inundation of structures and roads near streams. Some evacuations of people and/or transfer of property to higher elevations are necessary.
  • Major Flooding - extensive inundation of structures and roads. Significant evacuations of people and/or transfer of property to higher elevations.

The impacts of a floods vary locally.  For each NWS river forecast location, flood stage and the stage associated with each of the NWS flood severity categories are established in cooperation with local public officials.  Increasing river levels above flood stage constitute minor, moderate, and major flooding.  Impacts vary from one river location to another because a certain river stage (height) in one location may have an entirely different impact than the same level above flood stage at another location.

Q: What's the difference between a flood and flash flood?

A flood occurs when prolonged rainfall over several days, intense rainfall over a short period of time, or an ice or debris jam causes a river or stream to overflow and flood the surrounding area. Melting snow can combine with rain in the winter and early spring; severe thunderstorms can bring heavy rain in the spring and summer; or tropical cyclones can bring intense rainfall to the coastal and inland states in the summer and fall.

A flash floods occur within six hours of a rain event, or after a dam or levee failure, or following a sudden release of water held by an ice or debris jam, and flash floods can catch people unprepared. You will not always have a warning that these deadly, sudden floods are coming. So, if you live in areas prone to flash floods, plan now to protect your family and property. The use of the word “flash” here is synonymous with “urgent.”

Q: Is there anything I can do to prepare for a flood?

How to reduce potential flood damage and what to include in a family disaster plan can be obtained from the American Red Cross.

The NWS works with and relies on strategic partners involved in floodplain management, flood hazard mitigation, flood preparedness, and flood warnings to reduce the loss of life and property due to floods.  Key partners include the U.S. Geological Survey , FEMA, the National Hydrologic Warning Council, the Association of State Floodplain Managers, the American Red Cross, the National Safety Council, the Federal Alliance for Safe Homes, the media, and many other government and private sector organizations.



NOAA, National Weather Service
Office of Climate, Water, and Weather Services
1325 East West Highway
Silver Spring, MD 20910
Questions, Comments?

Disclaimer
Credits
Glossary
Privacy Policy
About Us
Career Opportunities
Last Updated: June 11, 2008