Alert archive / South Dakota / Flash Flood Warnings in 2021

Flash Flood Warning 6, NWS Sioux Falls, SD

August 28, 2021Lincoln County, Minnehaha County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at Aug 28, 2021, 10:36 PM CDT for Lincoln County, Minnehaha County, South Dakota. It was in force for 114 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 28, 2021, 10:36 PM CDT (03:36 UTC)
Expired: Aug 29, 2021, 12:30 AM CDT
In force: 114 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Flood severity: None

Counties Lincoln County, SD, Minnehaha County, SD

The radar

The Sioux Falls radar (KFSD), 11 km from the middle of the area, began a volume at 03:35 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, 3.6 hours before the alert went out and 209 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: 143 J/kg
Mixed-layer CIN: -122 J/kg
Mixed-layer LCL: 1242 m above ground
0-6 km bulk shear: 71 kt
0-1 km storm-relative helicity: -15 m²/s²
0-3 km storm-relative helicity: 268 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

158 
WGUS53 KFSD 290336
FFWFSD
SDC083-099-290530-
/O.NEW.KFSD.FF.W.0006.210829T0336Z-210829T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
1036 PM CDT Sat Aug 28 2021

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Northwestern Lincoln County in southeastern South Dakota...
  Southeastern Minnehaha County in southeastern South Dakota...

* Until 1230 AM CDT.

* At 1036 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain in Sioux Falls. Between 3 and 7 inches of rain have 
  fallen. Additional rainfall amounts up to 1 inch are possible with 
  the heaviest rainfall expected south of 26th Street. Flash 
  flooding is already occurring.

  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...
  Sioux Falls, Brandon, Harrisburg, Tea, Lake Alvin State Recreation 
  Area and Rowena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4363 9683 4361 9651 4350 9656 4350 9660
      4348 9658 4348 9659 4347 9658 4346 9660
      4344 9660 4343 9660 4345 9689

FLASH FLOOD...RADAR INDICATED

$$

Schumacher

2 follow-up statements

098 
WGUS73 KFSD 290417
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
1117 PM CDT Sat Aug 28 2021

SDC083-099-290530-
/O.CON.KFSD.FF.W.0006.000000T0000Z-210829T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln SD-Minnehaha SD-
1117 PM CDT Sat Aug 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT SUNDAY 
FOR NORTHWESTERN LINCOLN AND SOUTHEASTERN MINNEHAHA COUNTIES...

At 1117 PM CDT, Doppler radar indicated thunderstorms had produced 
heavy rain in Sioux Falls. Between 3 and 7 inches of rain have 
fallen. The rain has ended but runoff will continue to cause 
flooding in low-lying areas.

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...
  Sioux Falls, Brandon, Harrisburg, Tea, Lake Alvin State Recreation 
  Area and Rowena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4363 9683 4361 9651 4350 9656 4350 9660
      4348 9658 4348 9659 4347 9658 4346 9660
      4344 9660 4343 9660 4345 9689

FLASH FLOOD...RADAR INDICATED

$$

Schumacher

175 
WGUS73 KFSD 290528
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
1228 AM CDT Sun Aug 29 2021

SDC083-099-290538-
/O.EXP.KFSD.FF.W.0006.000000T0000Z-210829T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln SD-Minnehaha SD-
1228 AM CDT Sun Aug 29 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1230 AM CDT EARLY THIS MORNING 
FOR NORTHWESTERN LINCOLN AND SOUTHEASTERN MINNEHAHA COUNTIES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4363 9683 4361 9651 4350 9656 4350 9660
      4348 9658 4348 9659 4347 9658 4346 9660
      4344 9660 4343 9660 4345 9689

$$

Dux

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 7:23 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Lincoln	52 min
Aug 28, 7:25 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Hanson, Lake, McCook, Miner, Minnehaha, Moody	50 min
Aug 28, 7:27 PM CDT	Severe Thunderstorm Warning	FSD	Bon Homme, Hutchinson, Turner, Yankton	48 min
Aug 28, 7:48 PM CDT	Severe Thunderstorm Warning	FSD	Lake, McCook, Minnehaha, Moody, Turner	31 min
Aug 28, 7:50 PM CDT	Severe Thunderstorm Warning	FSD	Bon Homme, Clay, Hutchinson, Lincoln, Turner, Yankton	40 min
Aug 28, 8:52 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha	23 min
Aug 28, 9:13 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln	47 min
Aug 28, 9:20 PM CDT	Flash Flood Warning	FSD	Lincoln, Minnehaha	85 min
Aug 28, 9:29 PM CDT	Flash Flood Warning	FSD	Lincoln, Minnehaha	3 hr
Aug 28, 11:46 PM CDT	River Flood Warning	FSD	Lincoln, Minnehaha	8 hr
Aug 29, 7:44 AM CDT	River Flood Warning	FSD	Lincoln	15 hr

Nearby

Flash Flood Warnings in South Dakota, 2021 Every 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.