Flash flood warning

Flash flood

Flash flood

A flash flood warning (SAME code: FFW) is issued when a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain, or occasionally after a dam break. Rainfall intensity and duration, topography, soil conditions, and ground cover contribute to flash flooding.

Most flash floods occur when there is a heavy amount of precipitation falling in an area and that water is then channeled through streams or narrow gullies. Flash floods may take minutes or hours to develop. It is possible to experience a flash flood without witnessing any rain. In this case, there would be heavy rain in areas upstream of the warned location.^[1]

Flash flood alerts

There are two types of alerts for flash floods which are issued by the National Weather Service. One is a flash flood watch, which means that conditions are favorable for flash flooding, and the other is a flash flood warning, meaning that a flash flood is occurring or one will occur imminently and is usually issued when there are strong weather radar echoes for an area that is prone to flash flooding.^[2] Flash floods can also occur because of a dam or levee failure,^[3] or because of a sudden release of water held by an ice jam.

Residents are usually urged to do the following when flash flooding is imminent:^[4]

Be aware of any signs of heavy rain
Move to higher ground if rapidly rising water is seen or heard
Not attempt to cross the flowing water

In addition, some NWS Weather Forecast Offices have instituted an enhanced flash flood warning, referred to as a flash flood emergency (or as termed by the Albany, New York office as a flash flood warning emergency^[5]), which indicates a severe flooding situation in densely populated areas, similar to the procedure for declaring a tornado emergency.

Example of a flash flood warning and emergency

Warning

	Flash flood warning Tennessee An example of a flash flood warning in Tennessee.
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FLASH FLOOD WARNING
KSC003-302230-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TOPEKA KS
1129 AM CDT SAT JUN 30 2007

THE NATIONAL WEATHER SERVICE IN TOPEKA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  ANDERSON COUNTY IN EAST CENTRAL KANSAS...

* UNTIL 530 PM CDT SATURDAY

* AT 1129 AM CDT...THE PUBLIC REPORTED WATER FLOWING OVER A COUPLE
OF PAVED ROADS NEAR WESTPHALIA.  ANDERSON COUNTY EMERGENCY
MANAGEMENT ALSO INDICATED THAT SEVERAL PAVED ROADS HAD WATER RISING
AND APPROACHING ROADWAYS.  DOPPLER RADAR INDICATED THAT ANOTHER BAND
OF HEAVY RAINFALL WAS DEVELOPING AND TRAINING OVER ANDERSON COUNTY
PRODUCING RAINFALL RATES UP TO ONE INCH PER HOUR.  ENHANCED RAINFALL
RATES WILL LIKELY BE ENOUGH TO BRING WATER OVER SEVERAL PAVED ROADS
IN THE COUNTY

* LOCATIONS IMPACTED INCLUDE...
  HARRIS...
  GREELEY...
  GARNETT...
  WESTPHALIA...

RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS AND
STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY ROADS AND FARMLANDS
ALONG THE BANKS OF CREEKS AND STREAMS AND LOW LYING AREAS ARE SUBJECT
TO FLASH FLOODING.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE PRECAUTIONS
TO PROTECT LIFE AND PROPERTY.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
TOPEKA.

STAY TUNED TO NOAA WEATHER RADIO OR LOCAL MEDIA OUTLETS FOR THE
LATEST INFORMATION CONCERNING THE SEVERE WEATHER.

LAT...LON 3803 9551 3803 9507 3839 9506 3838 9550

$$

Emergency

	Flash flood emergency Tennessee An example of a flash flood emergency in Tennessee.
Problems playing this file? See media help.


FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
210 PM CDT SAT JUN 30 2007

KSC003-302230-
ANDERSON-
210 PM CDT SAT JUN 30 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR
ANDERSON COUNTY...

.A FLASH FLOOD EMERGENCY FOR ANDERSON COUNTY...

AT 200 PM CDT...TRAINED WEATHER SPOTTERS AND PUBLIC REPORTED
WIDESPREAD FLOODING OVER ANDERSON COUNTY. KNOWN WATER RESCUES ARE
ONGOING WEST OF GARNETT. EMERGENCY CREWS ARE UNABLE TO FIND A ROUTE
FROM WESTPHALIA TO GARNETT. NUMEROUS PAVED AND GRAVEL ROADS HAVE
BEEN REPORTED TO BE UNDER WATER ACROSS THE COUNTY....SEVERAL AREAS 1
TO 2 FEET DEEP. MEASURED STORM TOTAL PRECIPITATION AMOUNTS RANGE
FROM 14 TO 16 INCHES OF RAINFALL DURING THE PAST THREE DAYS. WITH
ONGOING RAINFALL AMOUNTS ON THE ORDER OF 1 TO 2 INCHES PER
HOUR...ANY ADDITIONAL RAINFALL WILL CONTINUE TO AGGRAVATE THE
FLOODING SITUATION.

LOCATIONS IMPACTED INCLUDE...
WESTPHALIA...COLONY...HARRIS...GREELEY AND GARNETT.

RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS AND
STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY ROADS AND FARMLANDS
ALONG THE BANKS OF CREEKS AND STREAMS AND LOW LYING AREAS ARE LIKELY
TO CONTINUE OR QUICKLY BEGIN TO FLASH FLOOD. DO NOT DRIVE INTO AREAS
WHERE THE WATER COVERS THE ROAD.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE PRECAUTIONS
TO PROTECT LIFE AND PROPERTY.

LAT...LON 3803 9551 3803 9507 3839 9506 3838 9550

$$

BLAIR / CAVANAUGH

References

↑ "NOAA".
↑ "Stormwarn.com".
↑ "New Orleans Levee Breach Flash Flood Warning".
↑ "NOAAWatch Home". Retrieved 17 January 2014.
↑ NWGeek on YouTube. "NWS Albany Flash Flood Warning Emergency EAS - Newfane, VT". NWRGeek. NWRGeek Productions. Retrieved 1 August 2012.

Severe weather terminology in the United States

Severe
storms

Thunderstorm	Advisory Watch PDS Watch Warning

Tornado	Watch PDS Watch Warning PDS Warning Emergency

Marine Thunderstorm	Special marine warning

Winter
weather

Advisories	Winter Weather Advisory

Winter storm	Watch Warning

Blizzard/Blowing Snow	Blowing Snow advisory Blizzard watch Blizzard warning

Heavy snow	Warning

Lake-effect snow	Advisory Watch Warning

Ice	Freezing rain advisory Ice storm warning

Tropical
Cyclones

Tropical storms	Watch Warning

Hurricanes	Watch Warning

Inland Advisories	Inland Tropical Storm Watch Inland Tropical Storm Warning Inland Hurricane Watch Inland Hurricane Warning

Hurricane Local Statement

Flood

Flood	Watch Warning

Flash flood	Watch PDS Watch Warning Emergency

Coastal flood	Advisory Watch Warning

Lakeshore flood	Advisory Watch Warning Seiche Warning

River flood	Advisory Watch Warning

Urban and small stream flood	Advisory

Apparent
temperature

Heat index	Heat advisory Excessive heat watch Excessive heat warning

Wind chill	Advisory Watch Warning PDS Warning

Extreme cold	Watch Warning

Freeze	Watch Warning Hard Freeze Warning Frost Advisory

Maritime
and
coastal
weather

Marine Winds	Small craft advisory Brisk wind advisory Lake Wind Advisory

Gale	Watch Warning

Storm	Watch Warning

Hurricane Force Wind	Watch Warning

Hazardous Seas	Watch Warning

Freezing Spray	Freezing spray advisory Heavy freezing spray watch Heavy freezing spray warning

High Surf	Advisory Warning

Wind

Advisory-Force Winds	Wind Advisory

Gale-Force Winds	High wind watch High wind warning

Major Hurricane-Force Winds	Extreme wind warning

Airborne
particulates

Dust/sand	Blowing Dust Advisory Dust Storm Warning

Fog/Smoke	Dense Fog Advisory Dense Smoke Advisory

Ash	Ashfall Advisory

Air pollution	Air Stagnation Advisory

Fire

Aviation

Center Weather Advisory
SIGMET
Volcanic Ash Advisory

Weather scales
used by NWS

Beaufort (wind)
Enhanced Fujita (tornadoes)
Saffir-Simpson Hurricane Scale (tropical cyclones)

Other

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