Alert archive / Iowa / Flash Flood Warnings in 2012

Flash Flood Warning 3, NWS La Crosse, WI

September 4, 2012Allamakee County, Clayton County, Iowa; Crawford County, Grant County, Wisconsin

NWS La Crosse, WI issued this flash flood warning at Sep 4, 2012, 8:09 PM CDT for Allamakee County, Clayton County, Iowa; Crawford County, Grant County, Wisconsin. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 4, 2012, 8:09 PM CDT (01:09 UTC)
Expired
Sep 5, 2012, 2:00 AM CDT
In force
6 hr
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Flood severity
None

Counties Allamakee County, IA, Clayton County, IA, Crawford County, WI, Grant County, WI

The radar

The La Crosse radar (KARX), 89 km from the middle of the area, began a volume at 01:11 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.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.2 hours before the alert went out and 164 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-pSkew-T log-p diagram, Davenport, at 00:00Z on 2012-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1890 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2012-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1890 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
1662 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.9

Open this sounding in Storm Lab

The text

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

153 
WGUS53 KARX 050109
FFWARX
IAC005-043-WIC023-043-050700-
/O.NEW.KARX.FF.W.0003.120905T0109Z-120905T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
809 PM CDT TUE SEP 4 2012

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEAST CLAYTON COUNTY IN NORTHEAST IOWA...  
  SOUTHEASTERN ALLAMAKEE COUNTY IN NORTHEAST IOWA...  
  SOUTHWESTERN CRAWFORD COUNTY IN SOUTHWEST WISCONSIN...  
  NORTHWEST GRANT COUNTY IN SOUTHWEST WISCONSIN...

* UNTIL 200 AM CDT

* AT 803 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE      
  WARNED AREA. DOPPLER RADAR INDICATES 3 TO 4 INCHES OF RAIN HAS     
  FALLEN IN SOME AREAS WITHIN THE WARNING...AND MORE IS EXPECTED. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PRAIRIE DU CHIEN...BLOOMINGTON...HARPERS FERRY...MARQUETTE AND     
  MCGREGOR. 

MUDSLIDES ALONG HIGHWAY 35 ARE ALSO POSSIBLE IN THE WARNED AREA. 

THIS INCLUDES SOME OF THE FOLLOWING STREAMS AND DRAINAGES...

GASNER HOLLOW...MILLVILLE CREEK...MARTIN BRANCH...LITTLE KICKAPOO 
CREEK...LITTLE GREEN RIVER...LANE CREEK...LITTLE GRANT RIVER...GRANT 
RIVER...BLOODY RUN...BLAKE FORK...PLUM CREEK...MILL COULEE 
CREEK...AND RUSH CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. TURN AROUND AND MOVE UP TO HIGHER GROUND TO 
ESCAPE FLOOD WATERS. 

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4295 9115 4301 9123 4308 9129 4328 9141
      4328 9110 4288 9071 4276 9084

$$

BAUMGARDT
3 follow-up statements
648 
WGUS73 KARX 050204
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
904 PM CDT TUE SEP 4 2012

IAC005-043-WIC023-043-050700-
/O.CON.KARX.FF.W.0003.000000T0000Z-120905T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLAMAKEE IA-CLAYTON IA-CRAWFORD WI-GRANT WI-
904 PM CDT TUE SEP 4 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWEST GRANT... 
SOUTHWESTERN CRAWFORD...NORTHEAST CLAYTON AND SOUTHEASTERN ALLAMAKEE 
COUNTIES UNTIL 200 AM CDT...

AT 858 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL CONTINUE ACROSS THE WARNED 
AREA. THE STORMS HAVE BEEN REPEATING OVER THE SAME AREAS FOR MANY 
HOURS. HOWEVER...THERE HAS BEEN SOME SOUTHWARD MOVEMENT TO THE 
STORMS...AND ALLAMAKEE COUNTY MAY BE OUT OF THE RAINFALL BY 10 PM. 

DOPPLER RADAR RAINFALL ESTIMATES OF OVER 4 INCHES ARE COMMON IN THE 
WARNED AREA FROM ABOUT HARPERS FERRY IOWA...TO JUST EAST OF PRAIRIE 
DU CHIEN...TO JUST NORTHWEST OF LANCASTER. AROUND 3 INCHES OF RAIN 
HAS FALLEN IN PRAIRIE DU CHIEN. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...PRAIRIE
DU CHIEN...BLOOMINGTON...HARPERS FERRY...MARQUETTE AND MCGREGOR. 
MUDSLIDES MAY OCCUR ALONG HIGHWAY 35.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE 
WATER COVERS THE ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW 
YOUR CAR TO CROSS SAFELY.

&&

LAT...LON 4295 9115 4301 9123 4308 9129 4328 9141
      4328 9110 4288 9071 4276 9084

$$
896 
WGUS73 KARX 050303
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1003 PM CDT TUE SEP 4 2012

IAC005-043-WIC023-043-050700-
/O.CON.KARX.FF.W.0003.000000T0000Z-120905T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLAMAKEE IA-CLAYTON IA-CRAWFORD WI-GRANT WI-
1003 PM CDT TUE SEP 4 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWEST 
GRANT...SOUTHWESTERN CRAWFORD...NORTHEAST CLAYTON AND SOUTHEASTERN 
ALLAMAKEE COUNTIES UNTIL 200 AM CDT...

AT 957 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS PRODUCED VERY HEAVY RAINFALL ACROSS THE WARNED AREA 
EARLIER THIS EVENING. RADAR ESTIMATES THAT 3 TO 4 INCHES OF RAIN 
FELL. THUNDERSTORMS HAVE TAPERED OFF BUT ADDITIONAL THUNDERSTORMS 
ARE POSSIBLE OVERNIGHT. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...PRAIRIE
DU CHIEN...BLOOMINGTON...HARPERS FERRY...MARQUETTE AND MCGREGOR.

LOCAL LAW ENFORCEMENT REPORTS SOME AREA CREEKS ARE RUNNING NEAR 
BANKFULL OVER NORTHWEST GRANT COUNTY. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4295 9115 4301 9123 4308 9129 4328 9141
      4328 9110 4288 9071 4276 9084

$$

JW
843 
WGUS73 KARX 050606
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
106 AM CDT WED SEP 5 2012

IAC005-043-WIC023-043-050700-
/O.CON.KARX.FF.W.0003.000000T0000Z-120905T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLAMAKEE IA-CLAYTON IA-CRAWFORD WI-GRANT WI-
106 AM CDT WED SEP 5 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR WEST CENTRAL GRANT...
SOUTHWESTERN CRAWFORD...NORTH CENTRAL CLAYTON AND SOUTHEASTERN
ALLAMAKEE COUNTIES UNTIL 200 AM CDT...

HEAVY RAIN HAS FALLEN ACROSS THE AREA TUESDAY EVENING...WITH RADAR 
ESTIMATING UPWARDS OF 3 INCHES FROM NEAR HARPERS FERRY TO LANCASTER. 
ADDITIONAL RAINFALL OF AROUND AN INCH IS POSSIBLE EARLY THIS MORNING 
AS MORE SHOWERS AND THUNDERSTORMS MOVE THROUGH. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...PRAIRIE
DU CHIEN...BLOOMINGTON...HARPERS FERRY...MARQUETTE AND MCGREGOR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4295 9115 4301 9123 4308 9129 4328 9141
      4328 9110 4288 9071 4276 9084

$$

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 4, 7:06 PM CDTSevere Thunderstorm WarningARXAllamakee24 min
Sep 4, 7:35 PM CDTSevere Thunderstorm WarningARXClayton70 min
Sep 4, 10:10 PM CDTSevere Thunderstorm WarningARXClayton, Fayette65 min
Sep 4, 10:42 PM CDTSevere Thunderstorm WarningARXAllamakee, Winneshiek33 min
Sep 4, 11:09 PM CDTFlash Flood WarningARXAllamakee, Winneshiek5 hr
Sep 4, 11:14 PM CDTSevere Thunderstorm WarningARXClayton46 min
Sep 4, 11:36 PM CDTSevere Thunderstorm WarningARXAllamakee, Clayton, Fayette, Winneshiek47 min
Sep 4, 11:59 PM CDTSevere Thunderstorm WarningARXClayton61 min
Sep 5, 12:12 AM CDTSevere Thunderstorm WarningARXFloyd, Mitchell63 min
Sep 5, 12:31 AM CDTSevere Thunderstorm WarningARXChickasaw, Howard44 min
Sep 5, 1:06 AM CDTSevere Thunderstorm WarningARXFayette, Winneshiek24 min
Sep 5, 1:28 AM CDTSevere Thunderstorm WarningARXAllamakee32 min
Sep 5, 1:51 AM CDTFlash Flood WarningARXClayton, Fayette3 hr
Sep 5, 1:59 AM CDTFlash Flood WarningARXAllamakee, Clayton3 hr
Sep 4, 7:00 PM CDTSevere Thunderstorm WarningARXGrant60 min
Sep 4, 7:10 PM CDTSevere Thunderstorm WarningARXRichland65 min
Sep 4, 7:41 PM CDTTornado WarningARXGrant34 min
Sep 4, 8:51 PM CDTSevere Thunderstorm WarningARXGrant39 min
Sep 5, 1:48 AM CDTSevere Thunderstorm WarningARXLa Crosse, Vernon27 min

Nearby

Flash Flood Warnings in Iowa, 2012Flash Flood Warnings in Wisconsin, 2012Every flash flood warning in 2012

Sources

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