Alert archive / Iowa / Flash Flood Warnings in 2009

Flash Flood Warning 2, NWS La Crosse, WI

April 26, 2009Clayton County, Fayette County, Iowa; Grant County, Wisconsin

NWS La Crosse, WI issued this flash flood warning at Apr 26, 2009, 7:11 PM CDT for Clayton County, Fayette County, Iowa; Grant County, Wisconsin. It was in force for 6 hr. 2 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: Apr 26, 2009, 7:11 PM CDT (00:11 UTC)
Expired: Apr 27, 2009, 1:00 AM CDT
In force: 6 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

Counties Clayton County, IA, Fayette County, IA, Grant County, WI

The radar

The La Crosse radar (KARX), 111 km from the middle of the area, began a volume at 00:11 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.

What was reported inside it

Time	Report	Where	Remark
Apr 26, 9:45 PM CDT	FLASH FLOOD	1 N Marquette, IA	LAW ENFORCEMENT REPORTS HIGHWAY 76 CLOSED JUST NORTH OF MARQUETTE DUE TO A MUD SLIDE.
Apr 26, 10:38 PM CDT	FLASH FLOOD	2 N Bagley, WI	2 FEET OF WATER OVER COUNTY HIGHWAY X

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, 0.2 hours before the alert went out and 141 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: 19 J/kg
Mixed-layer CIN: -108 J/kg
Mixed-layer LCL: 2074 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 196 m²/s²
0-3 km storm-relative helicity: 305 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KARX 270011
FFWARX
IAC043-065-WIC043-270600-
/O.NEW.KARX.FF.W.0002.090427T0011Z-090427T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
711 PM CDT SUN APR 26 2009

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLAYTON COUNTY IN NORTHEAST IOWA
  FAYETTE COUNTY IN NORTHEAST IOWA
  GRANT COUNTY IN SOUTHWEST WISCONSIN

* UNTIL 100 AM CDT

* AT 708 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THUNDERSTORMS WITH VERY HEAVY RAINFALL MOVING ACROSS THE           
  WARNED AREA. THESE THUNDERSTORMS WILL BE CAPABLE OF PRODUCING      
  RAINFALL RATES OF 1 TO 2 INCHES PER HOURS. ALTHOUGH BREAKS FROM    
  THE RAIN ARE POSSIBLE....MORE THUNDERSTORMS ACROSS CENTRAL IOWA    
  WILL MOVE INTO THE AREA LATER THIS EVENING. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ELKADER...GUTTENBERG...LANCASTER...OELWEIN...PLATTEVILLE...WEST    
  UNION...BLOOMINGTON...BOSCOBEL...CASSVILLE...  CLERMONT...CUBA     
  CITY...DICKEYVILLE...ELGIN...FAYETTE AND HAZEL GREEN.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING WARNING MEANS THAT FLOODING IS IMMINENT OR
OCCURRING. IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND
IMMEDIATELY. RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE
IMMEDIATE PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO
CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 4254 9064 4264 9071 4268 9088 4264 9090
      4264 9208 4309 9208 4308 9116 4300 9115
      4299 9107 4308 9083 4318 9067 4321 9055
      4320 9042 4251 9041 4251 9064

$$

RABERDING

3 follow-up statements

000 
WGUS73 KARX 270133
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
833 PM CDT SUN APR 26 2009

IAC043-065-WIC043-270600-
/O.CON.KARX.FF.W.0002.000000T0000Z-090427T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-CLAYTON IA-GRANT WI-
833 PM CDT SUN APR 26 2009

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR GRANT...CLAYTON AND
FAYETTE COUNTIES UNTIL 100 AM CDT...

AT 830 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS WITH VERY 
HEAVY RAINFALL ACROSS THE WARNED AREA. DOPPLER RADAR ESTIMATED 
RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WITH THE STRONGER STORMS. 
THIS STRONGEST BAND OF STORMS WILL MOVE ACROSS EASTERN CLAYTON AND 
GRANT COUNTIES THROUGH 10 PM FOLLOWED WITH MODERATE RAIN ELSEWHERE. 

THUNDERSTORMS ARE PRODUCING VERY HEAVY RAINFALL IN THE WARNED AREA. 
RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING 
INCLUDE...ELKADER...GUTTENBERG...LANCASTER...OELWEIN...PLATTEVILLE...
WEST UNION...BOSCOBEL...CASSVILLE...FAYETTE...GARNAVILLO...HAZEL 
GREEN...MARQUETTE.

LOCAL LAW ENFORCEMENT REPORTED MAIN STREET IN MCGREGOR WAS CLOSED 
EARLIER THIS EVENING DUE TO FLOODING BUT HAS IS NOW OPEN AGAIN FOR 
TRAFFIC. ALSO A ROAD JUST OUTSIDE OF ELKADER WAS CLOSED DUE TO 
FLOODING.

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.

&&

LAT...LON 4254 9064 4264 9071 4268 9088 4264 9090
      4264 9208 4309 9208 4308 9116 4300 9115
      4299 9107 4308 9083 4318 9067 4321 9055
      4320 9042 4251 9041 4251 9064

$$

RABERDING

000 
WGUS73 KARX 270252
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
952 PM CDT SUN APR 26 2009

IAC043-065-WIC043-270600-
/O.CON.KARX.FF.W.0002.000000T0000Z-090427T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-CLAYTON IA-GRANT WI-
952 PM CDT SUN APR 26 2009

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR GRANT...CLAYTON AND
FAYETTE COUNTIES UNTIL 100 AM CDT...

AT 950 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED HIGHWAY 76 
JUST NORTH OF MARQUETTE IOWA CLOSED DUE TO A MUD SLIDE.

DOPPLER RADAR CONTINUES TO SHOW LIGHT TO AT TIMES MODERATE RAIN OVER 
THE WARNED AREA. THE RAIN HAS DECREASED IN INTENSITY WITH ONLY A 
TENTH TO ONE QUARTER OF AN INCH RAINFALL RATES EXPECTED FOR THE NEXT 
FEW HOURS. HOWEVER...WITH STREAMS AND RIVERS RUNNING NEAR BANK 
FULL...ANY ADDITIONAL RAIN WILL CONTINUE THE THREAT OF FLASH 
FLOODING.

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.

&&

LAT...LON 4254 9064 4264 9071 4268 9088 4264 9090
      4264 9208 4309 9208 4308 9116 4300 9115
      4299 9107 4308 9083 4318 9067 4321 9055
      4320 9042 4251 9041 4251 9064

$$

RABERDING

000 
WGUS73 KARX 270401
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1001 PM CDT SUN APR 26 2009

IAC043-065-WIC043-270600-
/O.CON.KARX.FF.W.0002.000000T0000Z-090427T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FAYETTE IA-CLAYTON IA-GRANT WI-
1101 PM CDT SUN APR 26 2009

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR GRANT...CLAYTON AND
FAYETTE COUNTIES UNTIL 100 AM CDT...

AT 11 PM CDT...WEATHER SPOTTERS REPORTED THAT COUNTY HIGHWAY X 
JUST NORTH OF BAGLEY HAD 2 FEET OF WATER OVER THE ROAD. 

DOPPLER RADAR INDICATED MORE MODERATE TO HEAVY RAIN WAS MOVING INTO 
THE WARNED AREA. THIS RAIN WILL ONLY AGRRAVATE FLASH FLOODING IN THE 
WARNED AREA.  

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.

&&

LAT...LON 4254 9064 4264 9071 4268 9088 4264 9090
      4264 9208 4309 9208 4308 9116 4300 9115
      4299 9107 4308 9083 4318 9067 4321 9055
      4320 9042 4251 9041 4251 9064

$$

RABERDING

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 26, 9:15 PM CDT	River Flood Warning	ARX	Clayton	24 hr
Apr 26, 9:15 PM CDT	River Flood Warning	ARX	Clayton	24 hr
Apr 27, 1:05 AM CDT	Areal Flood Warning	ARX	Clayton, Fayette	3 hr
Apr 26, 8:57 PM CDT	River Flood Warning	ARX	Richland, Vernon	13 hr
Apr 26, 8:57 PM CDT	River Flood Warning	ARX	Crawford, Vernon	13 hr
Apr 26, 8:57 PM CDT	River Flood Warning	ARX	Crawford	24 hr
Apr 26, 8:57 PM CDT	River Flood Warning	ARX	Crawford	24 hr

Nearby

Flash Flood Warnings in Iowa, 2009 Flash Flood Warnings in Wisconsin, 2009 Every flash flood warning in 2009

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.