Alert archive / Iowa / Flash Flood Warnings in 2004

Flash Flood Warning 34, NWS Sioux Falls, SD

September 17, 2004Clay County, Iowa

NWS Sioux Falls, SD issued this flash flood warning at Sep 17, 2004, 1:12 PM CDT for Clay County, Iowa. 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
Sep 17, 2004, 1:12 PM CDT (18:12 UTC)
Expired
Sep 17, 2004, 4:15 PM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Counties, with a storm outline in the text

County Clay County, IA

The radar

The Sioux Falls radar (KFSD), 133 km from the middle of the area, began a volume at 18:12 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 12:00Z, 6.2 hours before the alert went out and 221 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-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2004-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2004-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 204 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2346 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
204 m²/s²
0-3 km storm-relative helicity
267 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

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

000 
WGUS53 KFSD 171814
FFWFSD
IAC041-172115-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
112 PM CDT FRI SEP 17 2004

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CLAY COUNTY IN NORTHWEST IOWA

* UNTIL 415 PM CDT

* AT 112 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM THUNDERSTORMS ALONG A LINE EXTENDING FROM 5
  MILES NORTH OF EVERLY TO 8 MILES SOUTHWEST OF ROYAL...MOVING EAST
  AT 30 MPH.

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE 
WARNED AREA. THE GROUND IS ALREADY SATURATED AND FLOODING IS LIKELY.
THE RAIN SHOULD TAPER OFF BY 2 PM CDT...BUT FLOODING SHOULD CONTINUE.

LAT...LON 4325 9540 4292 9540 4292 9493 4325 9494

$$
RSR
4 follow-up statements
000 
WGUS73 KFSD 171842
FFSFSD
IAC041-172115-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
141 PM CDT FRI SEP 17 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 415 PM CDT FOR CLAY
COUNTY...

AT 141 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE THUNDERSTORMS PRODUCING FLASH FLOODING.  THESE STORMS WERE 
LOCATED ALONG A LINE EXTENDING FROM JUST SOUTH OF SPENCER TO 6 MILES 
SOUTH OF GREENVILLE...MOVING EAST AT 30 MPH.

AT 137 PM CDT...STREET AND BASEMENT FLOODING WAS REPORTED AT ROYAL.

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.

LAT...LON 4325 9540 4292 9540 4292 9493 4325 9494

$$
RSR
000 
WGUS73 KFSD 171927
FFSFSD
IAC041-172115-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
227 PM CDT FRI SEP 17 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 415 PM CDT FOR CLAY
COUNTY...

AT 227 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE THUNDERSTORMS PRODUCING HEAVY RAINFALL ACROSS NORTHERN CLAY 
COUNTY.  THESE STORMS ARE MOVING TO THE EAST 30 MPH.  
RAIN..OCCASIONALLY HEAVY...WILL CONTINUE OVER NORTHERN CLAY 
COUNTY...INCLUDING THE CITY OF SPENCER...THROUGH 3 PM.  

ADDITIONAL RAINFALL AMOUNTS OF UP TO AN INCH ARE POSSIBLE IN THE 
WARNED AREA.  THIS IS IN ADDITION TO THE 1 TO 3 INCHES THAT HAS 
ALREADY FALLEN THIS AFTERNOON.

BROADCAST MEDIA HAS REPORTED THAT ROYAL HAS RECEIVED 3 INCHES OF 
RAIN...WITH 1.25 INCHES OF RAIN REPORTED IN SPENCER.  STREET 
FLOODING WAS REPORTED IN ROYAL.  MINOR STREAT FLOODING WAS ALSO 
REPORTED IN PARTS OF SPENCER.

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 4325 9540 4292 9540 4292 9493 4325 9494

$$

SCHUMACHER
000 
WGUS73 KFSD 171952
FFSFSD
IAC041-172115-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
252 PM CDT FRI SEP 17 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 415 PM CDT FOR CLAY
COUNTY...

AT 252 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE NUMEROUS THUNDERSTORMS PRODUCING HEAVY RAINFALL ACROSS 
NORTHERN CLAY COUNTY. THE STORMS EXTENDED FROM HARTLEY THROUGH 
SPENCER. THE STORMS WERE MOVING TO THE EAST AT 30 MPH. 
RAINFALL..OCCASIONALLY HEAVY...WILL CONTINUE AROUND 
MONETA...SPENCER...AND DICKENS.

ADDITIONAL RAINFALL AMOUNTS OF AROUND ONE INCH ARE POSSIBLE IN THE 
ALONG AND SOUTH OF HIGHWAY 18 IN CLAY COUNTY THROUGH 330 PM CDT.

BROADCAST MEDIA REPORTED THAT 3.7 INCHES OF RAIN HAS FALLEN AT THE 
CLAY COUNTY FAIRGROUNDS IN SPENCER.  SPENCER AIRPORT REPORTED AROUND 
2.25 INCHES OF RAIN. STREET FLOODING WAS REPORTED IN SPENCER AND 
ROYAL. IN ADDITION...STONY CREEK WEST OF SPENCER MAY RISE ABOVE 
FLOOD STAGE DUE TO THE HEAVY RAINFALL.

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 4325 9540 4292 9540 4292 9493 4325 9494

$$

SCHUMACHER
000 
WGUS73 KFSD 172029
FFSFSD
IAC041-172115-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
329 PM CDT FRI SEP 17 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 415 PM CDT FOR CLAY
COUNTY...

AT 329 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A LINE OF THUNDERSTORMS PRODUCING FLASH FLOODING FROM 
MONETA TO GILLETT GROVE. THESE STORMS WERE MOVING TO THE EAST AT 30 
MPH.  RAINFALL...OCCASIONALLY HEAVY...WILL CONTINUE THROUGH 415 PM 
CDT ACROSS CENTRAL AND SOUTHERN CLAY COUNTY.  SCATTERED 
THUNDERSTORMS WILL ALSO CONTINUE NORTH OF HIGHWAY 18...INCLUDING THE 
CITY OF SPENCER

ADDITIONAL RAINFALL AMOUNTS OF UP TO ONE INCH ARE EXPECTED OVER 
PORTIONS OF SOUTHERN CLAY COUNTY...INCLUDING ROYAL.  UP TO ONE HALF 
INCH OF RAIN IS POSSIBLE ACROSS NORTHERN CLAY COUNTY...INCLUDING 
SPENCER.

BROADCAST MEDIA IN SPENCER REPORTED 2.92 INCHES OF RAIN THROUGH 315 
PM CDT...WITH UP TO 4 INCHES NEAR THE CLAY COUNTY FAIRGROUNDS.  OVER 
3 INCHES WAS OBSERVED NEAR ROYAL IOWA AROUND 2 PM CDT. STREET 
FLOODING WAS REPORTED IN SPENCER AND IN ROYAL.  SMALL CREEKS ACROSS 
THE COUNTY MAY ALSO RISE ABOVE FLOOD STAGE DUE TO THE HEAVY RAINFALL.

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.

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

LAT...LON 4325 9540 4292 9540 4292 9493 4325 9494

$$

SCHUMACHER

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 8:56 AM CDTSevere Thunderstorm WarningFSDSioux34 min
Sep 17, 1:49 PM CDTSevere Thunderstorm WarningFSDClay26 min
Sep 17, 4:14 PM CDTFlash Flood WarningFSDClay2 hr

Nearby

Flash Flood Warnings in Iowa, 2004Every flash flood warning in 2004

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.