Alert archive / Iowa / Flash Flood Warnings in 2011
Flash Flood Warning 33, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this flash flood warning at Aug 7, 2011, 11:10 PM CDT for Woodbury County, Iowa; Union County, South Dakota; Dakota County, Nebraska. It was in force for 80 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 7, 2011, 11:10 PM CDT (04:10 UTC)
- Expired
- Aug 8, 2011, 12:30 AM CDT
- In force
- 80 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Flood severity
- None
Counties Woodbury County, IA, Dakota County, NE, Union County, SD
The radar
The Omaha radar (KOAX), 126 km from the middle of the area, began a volume at 04:13 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
Omaha, NE (KOAX), launched 00:00Z, 4.2 hours before the alert went out and 126 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.
- Mixed-layer CAPE
- 1873 J/kg
- Mixed-layer CIN
- -119 J/kg
- Mixed-layer LCL
- 1289 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 33 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 3.1
The text
As transmitted, in the capitals the NWS used until 2016.
636
WGUS53 KFSD 080410
FFWFSD
IAC193-NEC043-SDC127-080530-
/O.NEW.KFSD.FF.W.0033.110808T0410Z-110808T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1110 PM CDT SUN AUG 7 2011
THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A
* FLASH FLOOD WARNING FOR...
NORTHEASTERN DAKOTA COUNTY IN NORTHEAST NEBRASKA
NORTHWESTERN WOODBURY COUNTY IN WEST CENTRAL IOWA
SOUTHEASTERN UNION COUNTY IN SOUTHEAST SOUTH DAKOTA
* UNTIL 1230 AM CDT
* AT 1106 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR
INDICATED THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED
AREA. ONE TO ONE AND ONE HALF INCHES OF RAIN CAN BE EXPECTED AS
THUNDERSTORMS MOVE ACROSS THE AREA. THE PRIMARY THREAT FOR FLASH
FLOODING WILL BE IN URBANIZED AREA WITH POOR DRAINAGE.
* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...SIOUX
CITY...DAKOTA CITY...NORTH SIOUX CITY...SERGEANT BLUFF...SOUTH
SIOUX CITY AND STONE STATE PARK.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.
&&
LAT...LON 4236 9644 4251 9662 4256 9650 4256 9633
4234 9617
$$
SCHUMACHER2 follow-up statements
195
WGUS73 KFSD 080447
FFSFSD
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1147 PM CDT SUN AUG 7 2011
IAC193-NEC043-SDC127-080530-
/O.CON.KFSD.FF.W.0033.000000T0000Z-110808T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WOODBURY IA-DAKOTA NE-UNION SD-
1147 PM CDT SUN AUG 7 2011
...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHEASTERN UNION...
NORTHEASTERN DAKOTA AND NORTHWESTERN WOODBURY COUNTIES UNTIL 1230 AM
CDT...
AT 1144 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS WITH VERY HEAVY RAINFALL WERE MOVING ACROSS THE SIOUX
CITY METROPOLITAN AREA. DOPPLER RADAR ESTIMATED THAT UP TO ONE HALF
INCH OF RAIN HAS FALLEN ACROSS THE AREA. AN ADDITIONAL ONE HALF TO
ONE INCH RAIN CAN BE EXPECTED THROUGH 1215 AM. THESE RAINFALL RATES
WILL CAUSE FLASH FLOODING IN URBANIZED AREAS WITH POOR DRAINAGE.
SLOW MOVING THUNDERSTORMS ARE PRODUCING VERY HEAVY RAINFALL IN THE
WARNED AREA. RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH
FLOODING TO OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING
INCLUDE...SIOUX CITY...DAKOTA CITY...NORTH SIOUX CITY...SERGEANT
BLUFF...SOUTH SIOUX CITY AND STONE STATE PARK.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE MINOR FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.
&&
LAT...LON 4236 9644 4251 9662 4256 9650 4256 9633
4234 9617
$$
SCHUMACHER413
WGUS73 KFSD 080522
FFSFSD
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1222 AM CDT MON AUG 8 2011
IAC193-NEC043-SDC127-080537-
/O.EXP.KFSD.FF.W.0033.000000T0000Z-110808T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WOODBURY IA-DAKOTA NE-UNION SD-
1222 AM CDT MON AUG 8 2011
...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHEASTERN
UNION...NORTHEASTERN DAKOTA AND NORTHWESTERN WOODBURY COUNTIES WILL
BE ALLOWED TO EXPIRE AT 1230 AM CDT...
EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED
AREA...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.
LAT...LON 4236 9644 4251 9662 4256 9650 4256 9633
4234 9617
$$
SCHUMACHERThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 11:12 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Woodbury | 48 min |
| Aug 7, 11:52 PM CDT | Severe Thunderstorm Warning | FSD | Ida, Woodbury | 38 min |
| Aug 7, 9:39 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Charles Mix, Gregory | 66 min |
| Aug 7, 10:33 PM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Clay, Union, Yankton | 57 min |
Nearby
Flash Flood Warnings in Iowa, 2011Flash Flood Warnings in South Dakota, 2011Flash Flood Warnings in Nebraska, 2011Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.