Alert archive / Iowa / Flash Flood Warnings in 2016

Flash Flood Warning 39, NWS La Crosse, WI

September 21, 2016Floyd County, Iowa

NWS La Crosse, WI issued this flash flood warning at Sep 21, 2016, 4:47 PM CDT for Floyd County, Iowa. It was in force for 4 hr. 1 report 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
Sep 21, 2016, 4:47 PM CDT (21:47 UTC)
Expired
Sep 21, 2016, 8:45 PM CDT
In force
4 hr
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Flood severity
None

County Floyd County, IA

The radar

The La Crosse radar (KARX), 159 km from the middle of the area, began a volume at 21:48 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

TimeReportWhereRemark
Sep 21, 7:30 PM CDTFLASH FLOODRudd, IASEVERAL MEDIA-RELAYED REPORTS OF WATER OVER ROADS AND IMPASSABLE IN RUDD AND ALSO ROCKFORD. POULTRY BARN REPORTED UNDERWATER IN RUDD.

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.8 hours before the alert went out and 198 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, Minneapolis, MN at 12:00Z on 2016-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 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, Minneapolis, MN at 12:00Z on 2016-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 square meters per square second.193958Sfc1 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
515 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

340 
WGUS53 KARX 212147
FFWARX
IAC067-220145-
/O.NEW.KARX.FF.W.0039.160921T2147Z-160922T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
447 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 845 PM CDT

* AT 444 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA...WITH 1 TO 3 INCHES ALREADY
  FALLEN. REPORTS OF DITCHES FULL OF WATER HAVE BEEN RECEIVED..AND
  WITH STORMS CONTINUING THIS EVENING CAPABLE OF PRODUCING ANOTHER 1
  TO 3 INCHES...FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  NORA SPRINGS...ROCKFORD...RUDD...
  IDLEWILDE STATE PARK AND HOWARDVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4321 9302 4321 9265 4293 9302

$$

AJ
3 follow-up statements
133 
WGUS73 KARX 212214
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
514 PM CDT WED SEP 21 2016

IAC067-220145-
/O.CON.KARX.FF.W.0039.000000T0000Z-160922T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLOYD IA-
514 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM CDT FOR
NORTHWESTERN FLOYD COUNTY...

AT 510 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
HEAVY RAIN ACROSS THE WARNED AREA. 1 TO 4 INCHES OF RAIN HAS ALREADY
FALLEN...HEAVIEST NEAR ROCKFORD. AT LEAST ANOTHER 1 TO 3 INCHES IS
POSSIBLE THIS EVENING WHICH WILL CAUSE FLASH FLOODING. LOCATIONS
NEAR ROCKFORD COULD PICK UP A TOTAL OF 6 TO 8 INCHES BY 9 PM.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
NORA SPRINGS...ROCKFORD...RUDD...
IDLEWILDE STATE PARK AND HOWARDVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4321 9302 4321 9265 4293 9302

$$

AJ
745 
WGUS73 KARX 212343
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
643 PM CDT WED SEP 21 2016

IAC067-220145-
/O.CON.KARX.FF.W.0039.000000T0000Z-160922T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLOYD IA-
643 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM CDT FOR
NORTHWESTERN FLOYD COUNTY...

AT 637 PM CDT...LAW ENFORCEMENT REPORTED NUMEROUS COUNTY ROADS
WITHWATER OVER THEM. DOPPLER RADAR ESTIMATES OF 2 TO 5 INCHES HAVE
ALREADY FALLEN...WITH ANOTHER 1 TO 3 INCHES POSSIBLE. THIS
ADDITIONAL RAIN WILL ONLY EXACERBATE ONGOING FLOODING.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
NORA SPRINGS...ROCKFORD...RUDD...
IDLEWILDE STATE PARK AND HOWARDVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4321 9302 4321 9265 4293 9302

$$

AJ
214 
WGUS73 KARX 220045
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
745 PM CDT WED SEP 21 2016

IAC067-220145-
/O.CON.KARX.FF.W.0039.000000T0000Z-160922T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLOYD IA-
745 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM CDT FOR
NORTHWESTERN FLOYD COUNTY...

AT 740 PM CDT...LOCAL LAW ENFORCEMENT REPORTED NUMEROUS FLOODED
ROADWAYS. ANY TRAVEL IS STRONGLY DISCOURAGED...ESPECIALLY NOW THAT
IT IS NIGHT. DOPPLER RADAR RAINFALL ESTIMATES WERE 4 TO 8 INCHES AND
ANOTHER 2 INCHES IS POSSIBLE BY 9 PM. THE FLASH FLOOD WARNING WILL
LIKELY BE EXTENDED WELL INTO THE NIGHT.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
NORA SPRINGS...ROCKFORD...RUDD...
IDLEWILDE STATE PARK AND HOWARDVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4321 9302 4321 9265 4293 9302

$$

AJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 6:44 AM CDTFlash Flood WarningARXAllamakee6 hr
Sep 21, 4:09 PM CDTSpecial Weather StatementARXFloyd51 min
Sep 21, 4:21 PM CDTSevere Thunderstorm WarningARXFloyd39 min
Sep 21, 5:03 PM CDTSevere Thunderstorm WarningARXFloyd57 min
Sep 21, 5:20 PM CDTTornado WarningARXFloyd40 min
Sep 21, 5:52 PM CDTSevere Thunderstorm WarningARXFloyd, Mitchell35 min
Sep 21, 6:01 PM CDTSevere Thunderstorm WarningARXFloyd44 min
Sep 21, 6:03 PM CDTFlash Flood WarningARXFloyd3 hr
Sep 21, 6:18 PM CDTTornado WarningARXFloyd42 min
Sep 21, 6:23 PM CDTFlash Flood WarningARXMitchell6 hr
Sep 21, 6:53 PM CDTTornado WarningARXChickasaw, Floyd32 min

Nearby

Flash Flood Warnings in Iowa, 2016Every flash flood warning in 2016

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.