Alert archive / Iowa / Flash Flood Warnings in 2011

Flash Flood Warning 14, NWS La Crosse, WI

July 22, 20114 counties in Iowa

NWS La Crosse, WI issued this flash flood warning at Jul 22, 2011, 4:52 AM CDT for 4 counties in Iowa. It was in force for 4 hr. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 22, 2011, 4:52 AM CDT (09:52 UTC)
Expired: Jul 22, 2011, 8:51 AM CDT
In force: 4 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

Counties Allamakee County, IA, Clayton County, IA, Fayette County, IA, Winneshiek County, IA

The radar

The La Crosse radar (KARX), 104 km from the middle of the area, began a volume at 09:53 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where
Jul 22, 5:00 AM CDT	HEAVY RAIN 2.14	Calmar, IA
Jul 22, 7:00 AM CDT	HEAVY RAIN 2.44	Calmar, IA
Jul 22, 7:00 AM CDT	HEAVY RAIN 3.25	Postville, IA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 9.9 hours before the alert went out and 156 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 889 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1773 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 119 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 3.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

479 
WGUS53 KARX 220952
FFWARX
IAC005-043-065-191-221400-
/O.NEW.KARX.FF.W.0014.110722T0952Z-110722T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
452 AM CDT FRI JUL 22 2011

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLAYTON COUNTY IN NORTHEAST IOWA...
  FAYETTE COUNTY IN NORTHEAST IOWA...
  SOUTHERN ALLAMAKEE COUNTY IN NORTHEAST IOWA...
  SOUTHERN WINNESHIEK COUNTY IN NORTHEAST IOWA...

* UNTIL 900 AM CDT

* AT 450 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE      
  WARNED AREA. RADAR ESTIMATES OF 2 TO 4 INCHES HAS FALLEN ACROSS    
  THE AREA SINCE 3 AM...WHICH WILL LEAD TO FLASH FLOODING. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ELKADER...GUTTENBERG...OELWEIN...WEST UNION...ARLINGTON...CALMAR...
  CLERMONT...FAYETTE...GARNAVILLO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. DO
NOT ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND TO
ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN
WATER BEGINS RISING.

&&

LAT...LON 4264 9208 4326 9208 4325 9108 4323 9107
      4313 9118 4291 9115 4288 9110 4274 9105
      4268 9095 4268 9090 4264 9090

$$

RABERDING

4 follow-up statements

257 
WGUS73 KARX 221032
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
532 AM CDT FRI JUL 22 2011

IAC005-043-065-191-221400-
/O.CON.KARX.FF.W.0014.000000T0000Z-110722T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-ALLAMAKEE IA-CLAYTON IA-WINNESHIEK IA-
532 AM CDT FRI JUL 22 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHERN WINNESHIEK...
CLAYTON...SOUTHERN ALLAMAKEE AND FAYETTE COUNTIES UNTIL 900 AM CDT...

AT 528 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. THE 
HEAVIEST RAIN WITH RATES OF 2 TO 3 INCHES PER HOUR HAD SHIFTED INTO 
THE SOUTHERN PARTS OF CLAYTON AND FAYETTE COUNTIES.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
ELKADER...GUTTENBERG...OELWEIN...WEST UNION...ARLINGTON...CALMAR...
CLERMONT...EDGEWOOD...ELGIN...FARMERSBURG...FAYETTE...FORT 
ATKINSON...GARNAVILLO.

RADAR ESTIMATES THAT 3 TO 5 INCHES OF RAIN HAS FALLEN OVER THE 
WARNED AREA OVER THE PAST 3 TO 4 HOURS. SOME STREAMS WITHIN THE 
HEAVIER RAIN BAND INCLUDE HICKORY CREEK AND WILLIAMS CREEK IN 
ALLAMAKEE COUNTY AND THE YELLOW RIVER AND DRY BRANCH IN WINNESHIEK 
COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD RELATED DEATHS OCCUR IN VEHICLES. DO NOT ATTEMPT TO CROSS
BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS THE ROADWAY.
NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT OR
IN A VEHICLE.

&&

LAT...LON 4264 9208 4326 9208 4325 9108 4323 9107
      4313 9118 4291 9115 4288 9110 4274 9105
      4268 9095 4268 9090 4264 9090

$$

RABERDING

773 
WGUS73 KARX 221110
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
610 AM CDT FRI JUL 22 2011

IAC005-043-065-191-221400-
/O.CON.KARX.FF.W.0014.000000T0000Z-110722T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-ALLAMAKEE IA-CLAYTON IA-WINNESHIEK IA-
610 AM CDT FRI JUL 22 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHERN WINNESHIEK...
CLAYTON...SOUTHERN ALLAMAKEE AND FAYETTE COUNTIES UNTIL 900 AM CDT...

AT 610 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. RADAR 
ESTIMATES HAVE RANGED FROM 3 TO 5 INCHES ACROSS THE WARNED AREA OVER 
THE PAST 3 TO 4 HOURS.

THE HEAVIEST RAIN HAS NOW SHIFTED OFF TO THE SOUTHEAST OF THE AREA. 
HOWEVER...SCATTERED THUNDERSTORMS WILL CONTINUE OVER THE AREA...WITH 
AN ADDITIONAL ONE HALF TO ONE INCH OF RAINFALL EXPECTED THROUGH 9 
AM. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
ELKADER...GUTTENBERG...OELWEIN...WEST UNION...ARLINGTON...CALMAR...
CLERMONT...EDGEWOOD...ELGIN...FARMERSBURG...FAYETTE...FORT 
ATKINSON...GARNAVILLO...HARPERS FERRY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD RELATED DEATHS OCCUR IN VEHICLES. DO NOT ATTEMPT TO CROSS
BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS THE ROADWAY.
NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT OR
IN A VEHICLE.

&&

LAT...LON 4264 9208 4326 9208 4325 9108 4323 9107
      4313 9118 4291 9115 4288 9110 4274 9105
      4268 9095 4268 9090 4264 9090

$$

RABERDING

993 
WGUS73 KARX 221237
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
737 AM CDT FRI JUL 22 2011

IAC005-043-065-191-221400-
/O.CON.KARX.FF.W.0014.000000T0000Z-110722T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-ALLAMAKEE IA-CLAYTON IA-WINNESHIEK IA-
737 AM CDT FRI JUL 22 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHERN WINNESHIEK...
CLAYTON...SOUTHERN ALLAMAKEE AND FAYETTE COUNTIES UNTIL 900 AM CDT...

AT 723 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS PRODUCED 2 TO 4 INCHES OF RAIN ACROSS PORTIONS OF THE 
WARNED AREA BETWEEN 3 AM AND 7 AM THIS MORNING. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING 
INCLUDE...ELKADER...GUTTENBERG...OELWEIN...WEST 
UNION...ARLINGTON...CALMAR...CLERMONT...GARNAVILLO...HARPERS 
FERRY...HAWKEYE...MCGREGOR...POSTVILLE...SPILLVILLE.

TRAINED WEATHER SPOTTERS REPORTED 3 AND A QUARTER INCHES OF RAINFALL 
IN POSTVILLE.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD RELATED DEATHS OCCUR IN VEHICLES. DO NOT ATTEMPT TO CROSS
BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS THE ROADWAY.
NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT OR
IN A VEHICLE.

&&

LAT...LON 4264 9208 4326 9208 4325 9108 4323 9107
      4313 9118 4291 9115 4288 9110 4274 9105
      4268 9095 4268 9090 4264 9090

$$

JW

152 
WGUS73 KARX 221351
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
851 AM CDT FRI JUL 22 2011

IAC005-043-065-191-221405-
/O.CAN.KARX.FF.W.0014.000000T0000Z-110722T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-ALLAMAKEE IA-CLAYTON IA-WINNESHIEK IA-
851 AM CDT FRI JUL 22 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHERN
WINNESHIEK...CLAYTON...SOUTHERN ALLAMAKEE AND FAYETTE COUNTIES IS
CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA AND 
ADDITIONAL HEAVY RAIN IS NOT EXPECTED. IF FLOODING HAS BEEN 
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4264 9208 4326 9208 4325 9108 4323 9107
      4313 9118 4291 9115 4288 9110 4274 9105
      4268 9095 4268 9090 4264 9090

$$

RIECK

Nearby

Flash Flood Warnings in Iowa, 2011 Every flash flood warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.