Alert archive / South Dakota / Flash Flood Warnings in 2021
Flash Flood Warning 7, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this flash flood warning at Aug 31, 2021, 12:00 AM CDT for Aurora County, Brule County, South Dakota. It was in force for 3 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
- Aug 31, 2021, 12:00 AM CDT (05:00 UTC)
- Expired
- Aug 31, 2021, 3:00 AM CDT
- In force
- 3 hr
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Flood severity
- None
Counties Aurora County, SD, Brule County, SD
The radar
The Aberdeen radar (KABR), 194 km from the middle of the area, began a volume at 05:02 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
Aberdeen, SD (KABR), launched 00:00Z, 5.0 hours before the alert went out and 137 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
- 205 J/kg
- Mixed-layer CIN
- -60 J/kg
- Mixed-layer LCL
- 1953 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 34 m²/s²
- 0-3 km storm-relative helicity
- 126 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
218
WGUS53 KFSD 310500
FFWFSD
SDC003-015-310800-
/O.NEW.KFSD.FF.W.0007.210831T0500Z-210831T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
1200 AM CDT Tue Aug 31 2021
The National Weather Service in Sioux Falls has issued a
* Flash Flood Warning for...
West Central Aurora County in south central South Dakota...
Central Brule County in south central South Dakota...
* Until 300 AM CDT.
* At 1200 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 3 inches of rain
have fallen. Additional rainfall amounts of 1 to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban
areas, highways, streets and underpasses as well as
other poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Chamberlain, Kimball, White Lake and Pukwana.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4380 9861 4364 9869 4370 9926 4375 9942
4378 9941 4379 9937 4382 9934 4386 9931
4387 9931 4391 9923
FLASH FLOOD...RADAR INDICATED
$$
SST2 follow-up statements
377
WGUS73 KFSD 310640
FFSFSD
Flash Flood Statement
National Weather Service Sioux Falls SD
140 AM CDT Tue Aug 31 2021
SDC003-015-310800-
/O.CON.KFSD.FF.W.0007.000000T0000Z-210831T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Aurora SD-Brule SD-
140 AM CDT Tue Aug 31 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 AM CDT EARLY THIS
MORNING FOR WEST CENTRAL AURORA AND CENTRAL BRULE COUNTIES...
At 140 AM CDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 2.5 and 3.5 inches of rain have
fallen. Additional rainfall amounts of 0.5 to 1 inch are possible in
the warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Chamberlain, Kimball, White Lake and Pukwana.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4378 9863 4364 9869 4370 9926 4375 9942
4377 9941 4379 9937 4382 9934 4386 9931
4387 9931 4389 9925
FLASH FLOOD...RADAR INDICATED
$$
SST591
WGUS73 KFSD 310753
FFSFSD
Flash Flood Statement
National Weather Service Sioux Falls SD
253 AM CDT Tue Aug 31 2021
SDC003-015-310803-
/O.EXP.KFSD.FF.W.0007.000000T0000Z-210831T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Aurora SD-Brule SD-
253 AM CDT Tue Aug 31 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 3 AM CDT EARLY THIS MORNING
FOR WEST CENTRAL AURORA AND CENTRAL BRULE COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4378 9863 4364 9869 4370 9926 4375 9942
4377 9941 4379 9937 4382 9934 4386 9931
4387 9931 4389 9925
$$
SSTThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 30, 7:29 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Union | 46 min |
| Aug 30, 7:57 PM CDT | Severe Thunderstorm Warning | FSD | Hutchinson, McCook, Minnehaha, Turner | 48 min |
| Aug 30, 11:19 PM CDT | Severe Thunderstorm Warning | FSD | Beadle, Jerauld, Sanborn | 41 min |
| Aug 31, 12:05 AM CDT | Severe Thunderstorm Warning | FSD | Aurora, Davison, Douglas | 40 min |
| Aug 31, 12:15 AM CDT | Severe Thunderstorm Warning | FSD | Hanson, Hutchinson | 45 min |
| Aug 31, 1:26 AM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Charles Mix, Gregory | 49 min |
| Aug 31, 2:14 AM CDT | Severe Thunderstorm Warning | FSD | Bon Homme, Charles Mix | 31 min |
Nearby
Flash Flood Warnings in South Dakota, 2021Every flash flood warning in 2021
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.