Bogley

[stefan]

one-stop flash flood watch/warning from the national weather service:

Flash Flood Forecast ~ National Weather Service

NWS : Flash Flood Safety Awareness (informative pdf)




TERMS/DEFINITIONS

Flash flood - A rapid (generally within six hours) rise of water along a stream or low-lying area after
a heavy rainfall or from the failure of a dam, levee, or ice jam. By definition, flash flooding is life-
threatening.

Flood - A flood occurs when water overflows the confines of a river, stream, or body of water, or ac-
cumulates in poorly drained low-lying or urban areas.

Hazardous Weather Outlook/Special Weather Statement - A Hazardous Weather Outlook/Special Weather Statement will be issued to alert the public of the potential for flooding/flash flooding. These products provide information on potentially hazardous weather out to 7 days.

Flash Flood Potential Rating - A qualitative rating (Low, Moderate, High, or Very High), indicative of the potential for flash flooding.

Flash Flood Watch - Issued when conditions are favorable for flash flooding. A watch usually gives 12 to 36 hours advance notice of the onset. A watch indicates a need for planning, preparation, and an increased awareness of changing weather conditions.

Flood Watch - Issued when conditions are favorable for river flooding. A watch usually gives 12 to 36 hours advance notice of the onset.

Flash Flood Warning - Issued when:
• Flash flooding is reported or imminent
• A dam or levee failure is imminent or occurring
• A sudden failure of a naturally-caused stream obstruction (including debris slide, avalanche, or ice jam) is imminent or occurring
• Precipitation capable of causing flash flooding is indicated by radar, rain gages, and/or satellite imagery.
• Local monitoring and prediction tools indicate flash flooding is likely

Flood Warning - Issued for flooding along rivers and streams. A warning indicates the need to take
immediate action to protect life and property. The two categories of flood warnings are:
• Point Specific Flooding Warning - Issued for specific river forecast points
• Areal Flood Warning - Issued for a generalized area