Alert archive / South Dakota / Flash Flood Warnings in 2010

Flash Flood Warning 2, NWS Sioux Falls, SD

April 24, 2010Minnehaha County, South Dakota; Lyon County, Iowa; Rock County, Minnesota

NWS Sioux Falls, SD issued this flash flood warning at Apr 24, 2010, 5:26 PM CDT for Minnehaha County, South Dakota; Lyon County, Iowa; Rock County, Minnesota. It was in force for 102 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: Apr 24, 2010, 5:26 PM CDT (22:26 UTC)
Expired: Apr 24, 2010, 7:08 PM CDT
In force: 102 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Flood severity: None

Counties Lyon County, IA, Rock County, MN, Minnehaha County, SD

The radar

The Sioux Falls radar (KFSD), 24 km from the middle of the area, began a volume at 22:30 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 12:00Z, 10.4 hours before the alert went out and 220 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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 461 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 26 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.

498 
WGUS53 KFSD 242226
FFWFSD
IAC119-MNC133-SDC099-250130-
/O.NEW.KFSD.FF.W.0002.100424T2226Z-100425T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
526 PM CDT SAT APR 24 2010

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN LYON COUNTY IN NORTHWEST IOWA
  SOUTHEASTERN MINNEHAHA COUNTY IN SOUTHEAST SOUTH DAKOTA
  SOUTHWESTERN ROCK COUNTY IN SOUTHWEST MINNESOTA

* UNTIL 830 PM CDT

* AT 516 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. 
  SLOW MOVING THUNDERSTORMS WILL PRODUCE VERY RAINFALL UP TO 2 INCHES
  IN THE WARNED AREA. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  LARCHWOOD AND ROWENA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL 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 SUBJECT TO FLOODING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 4355 9640 4355 9638 4342 9637 4342 9657
      4356 9656

$$
BUSS

1 follow-up statement

514 
WGUS73 KFSD 250008
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
708 PM CDT SAT APR 24 2010

IAC119-MNC133-SDC099-250023-
/O.CAN.KFSD.FF.W.0002.000000T0000Z-100425T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LYON IA-ROCK MN-MINNEHAHA SD-
708 PM CDT SAT APR 24 2010

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHEASTERN
MINNEHAHA...SOUTHWESTERN ROCK AND NORTHWESTERN LYON 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 4355 9640 4355 9638 4342 9637 4342 9657
      4356 9656

$$
BUSS

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 24, 2:10 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Hutchinson, McCook, Turner	50 min
Apr 24, 2:44 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Lake, McCook	46 min
Apr 24, 4:36 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha	24 min
Apr 24, 5:03 PM CDT	Flash Flood Warning	FSD	Minnehaha	2 hr
Apr 24, 5:32 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha	28 min
Apr 24, 5:19 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	26 min
Apr 24, 5:37 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	38 min
Apr 24, 6:10 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	35 min
Apr 24, 5:59 PM CDT	Severe Thunderstorm Warning	FSD	Rock	31 min

Nearby

Flash Flood Warnings in South Dakota, 2010 Flash Flood Warnings in Iowa, 2010 Flash Flood Warnings in Minnesota, 2010 Every flash flood warning in 2010

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.