Alert archive / South Dakota / Flash Flood Warnings in 2009

Flash Flood Warning 9, NWS Sioux Falls, SD

July 7, 2009Clay County, Yankton County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at Jul 7, 2009, 10:07 PM CDT for Clay County, Yankton County, South Dakota. It was in force for 88 min. 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: Jul 7, 2009, 10:07 PM CDT (03:07 UTC)
Expired: Jul 7, 2009, 11:35 PM CDT
In force: 88 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Flood severity: None

Counties Clay County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 85 km from the middle of the area, began a volume at 03:09 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
Jul 7, 10:30 PM CDT	FLASH FLOOD	Vermillion, SD	STREET FLOODING IN VERMILLION.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.1 hours before the alert went out and 182 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: 27 J/kg
Mixed-layer CIN: -201 J/kg
Mixed-layer LCL: 2298 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 157 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KFSD 080307
FFWFSD
SDC027-135-080500-
/O.NEW.KFSD.FF.W.0009.090708T0307Z-090708T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1007 PM CDT TUE JUL 7 2009

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLAY COUNTY IN SOUTHEAST SOUTH DAKOTA
  EASTERN YANKTON COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL MIDNIGHT CDT

* AT 1005 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR 
  INDICATED THUNDERSTORMS WITH VERY HEAVY RAINFALL MOVING SOUTH   
  ACROSS THE WARNED AREA. LOCALLY HEAVY RAINFALL AMOUNTS OF 2 TO
  3 INCHES CAN BE EXPECTED IN A SHORT TIME...WHICH WILL CAUSE 
  FLOODING. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  VERMILLION...IRENE...MAYFIELD...MECKLING...MISSION HILL...VOLIN AND
  WAKONDA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

&&

LAT...LON 4273 9689 4273 9696 4276 9698 4275 9702
      4281 9722 4285 9724 4286 9735 4287 9736
      4309 9735 4310 9718 4308 9716 4304 9681
      4271 9682

$$
CJ

2 follow-up statements

000 
WGUS73 KFSD 080401
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1101 PM CDT TUE JUL 7 2009

SDC027-135-080500-
/O.CON.KFSD.FF.W.0009.000000T0000Z-090708T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
YANKTON SD-CLAY SD-
1101 PM CDT TUE JUL 7 2009

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CLAY AND EASTERN YANKTON
COUNTIES UNTIL MIDNIGHT CDT...

AT 1059 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THE HEAVIEST RAINS HAVE MOVED OUT OF THE WARNED AREA. 
HOWEVER...THE HEAVY RAINS THAT DID FALL WILL CONTINUE TO PRODUCE 
AREAS OF FLASH FLOODING THROUGH MIDNIGHT. RADAR ESTIMATES OF 1 TO 2 
INCHES HAVE FALLEN ACROSS A LARGE PART OF THE WARNED AREA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLOODING OF SMALL CREEKS
AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY ROADS
AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW LYING
AREAS ARE ALSO SUBJECT TO FLOODING.

&&

LAT...LON 4273 9689 4273 9696 4276 9698 4275 9702
      4281 9722 4285 9724 4286 9735 4287 9736
      4309 9735 4310 9718 4308 9716 4304 9681
      4271 9682

$$
CJ

000 
WGUS73 KFSD 080435
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1135 PM CDT TUE JUL 7 2009

SDC027-135-080451-
/O.CAN.KFSD.FF.W.0009.000000T0000Z-090708T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
YANKTON SD-CLAY SD-
1135 PM CDT TUE JUL 7 2009

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR CLAY AND EASTERN
YANKTON COUNTIES IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA HAVE RECEDED OR WERE BEGINNING TO
RECEDE...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN OBSERVED...
PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4273 9689 4273 9696 4276 9698 4275 9702
      4281 9722 4285 9724 4286 9735 4287 9736
      4309 9735 4310 9718 4308 9716 4304 9681
      4271 9682

$$

CJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 7:32 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Kingsbury, Miner, Sanborn	43 min
Jul 7, 7:51 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln	39 min
Jul 7, 7:56 PM CDT	Flash Flood Warning	FSD	Lincoln, Minnehaha	2 hr
Jul 7, 7:57 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha, Turner	33 min
Jul 7, 8:23 PM CDT	Tornado Warning	FSD	Kingsbury, Miner, Sanborn	29 min
Jul 7, 8:51 PM CDT	Tornado Warning	FSD	Miner	24 min
Jul 7, 8:58 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Union	32 min
Jul 7, 9:10 PM CDT	Flash Flood Warning	FSD	Union	3 hr
Jul 7, 9:14 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Miner, Sanborn	46 min
Jul 7, 9:58 PM CDT	Severe Thunderstorm Warning	FSD	Davison, Hanson, McCook, Miner, Sanborn	47 min
Jul 7, 10:49 PM CDT	Severe Thunderstorm Warning	FSD	Union	41 min
Jul 8, 2:12 AM CDT	Flash Flood Warning	FSD	Union	3 hr

Nearby

Flash Flood Warnings in South Dakota, 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.