Flash flood warning

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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][not in citation given]

Flash flood alerts[edit]

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[edit]

Warning[edit]

An example of a flash flood warning in Tennessee.

Problems playing this file? See media help.

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[edit]

An example of a flash flood emergency in Tennessee.

Problems playing this file? See media help.

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DULUTH MN
940 PM CDT MON JUL 11 2016

MNC001-115-120400-
/O.CON.KDLH.FF.W.0005.000000T0000Z-160712T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
AITKIN MN-PINE MN-
940 PM CDT MON JUL 11 2016

...THIS IS A FLASH FLOOD EMERGENCY FOR PINE COUNTY...

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT FOR
SOUTHEASTERN AITKIN AND PINE COUNTIES...

AT 939 PM CDT...LOCAL LAW ENFORCEMENT AND EMERGENCY MANAGEMENT
REPORTED WIDESPREAD FLASH FLOODING OCCURRING ACROSS THE NORTHERN
HALF OF PINE COUNTY. MANY STATE... COUNTY...AND LOCAL ROADS ARE
UNDER WATER... AND SOME ROAD WASH OUTS HAVE BEEN REPORTED IN THE
STURGEON LAKE...WILLOW RIVER...DENHAM... BRUNO... ASKOV AND
SANDSTONE AREAS.

AT LEAST 5 TO 7 INCHES OF RAIN HAS ALREADY FALLEN ACROSS NORTHERN
PINE COUNTY...AND AN ADDITIONAL 3 TO 5 INCHES OF RAIN IS EXPECTED
OVER THE NEXT FEW HOURS.

THIS IS A FLASH FLOOD EMERGENCY FOR PINE COUNTY. THIS IS A
PARTICULARLY DANGEROUS AND LIFE-THREATENING SITUATION. SEEK HIGHER
GROUND NOW!  DO NOT TRAVEL UNLESS IT IS AN EMERGENCY AND DO NOT
DRIVE INTO AREAS WHERE WATER COVERS THE ROAD!

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
HINCKLEY...SANDSTONE...WILLOW RIVER...ASKOV...RUTLEDGE...
BROOK PARK...BRUNO...MCGRATH...HENRIETTE...CLOVERTON...DUXBURY...
FINLAYSON...NICKERSON...KERRICK...BEROUN...CLOVERDALE...HARLIS...
BELDEN...MARKVILLE AND FRIESLAND.

THIS ALSO INCLUDES INTERSTATE 35 BETWEEN HINCKLEY AND MOOSE LAKE...
AND STATE HIGHWAY 23 BETWEEN SANDSTONE AND HOLYOKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW! THIS IS AN EXTREMELY DANGEROUS AND LIFE-
THREATENING SITUATION! DO NOT ATTEMPT TO TRAVEL UNLESS YOU ARE
FLEEING AN AREA SUBJECT TO FLOODING OR UNDER AN EVACUATION ORDER.

ABANDON CAMPGROUNDS AND CAMP SITES NEAR STREAMS... CREEKS AND
RIVERS FOR HIGHER GROUND IMMEDIATELY!

TURN AROUND...DON`T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4598 9314 4598 9305 4616 9306 4615 9343
      4624 9343 4625 9352 4632 9355 4628 9313
      4642 9264 4642 9230 4607 9230 4602 9239
      4602 9243 4598 9250 4598 9253 4595 9256
      4587 9314

$$
 MILLER

See also[edit]

Severe weather terminology (United States)

References[edit]

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