Alert archive / Iowa / Flash Flood Warnings in 2011

Flash Flood Warning 1, NWS Des Moines, IA

February 17, 2011Dallas County, Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Feb 17, 2011, 1:47 PM CST for Dallas County, Polk County, Iowa. It was in force for 4 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
Feb 17, 2011, 1:47 PM CST (19:47 UTC)
Expired
Feb 17, 2011, 5:44 PM CST
In force
4 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

Counties Dallas County, IA, Polk County, IA

The radar

The Des Moines radar (KDMX), 21 km from the middle of the area, began a volume at 19:52 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, 7.8 hours before the alert went out and 219 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 2011-02-17Temperature 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 2011-02-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 square meters per square second.1939587897117136Sfc1 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
1561 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
202 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.

040 
WGUS53 KDMX 171947
FFWDMX
IAC049-153-180130-
/O.NEW.KDMX.FF.W.0001.110217T1947Z-110218T0130Z/
/00000.0.IJ.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
147 PM CST THU FEB 17 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR ICE JAM FLOODING IN...
  SOUTHEASTERN DALLAS COUNTY IN CENTRAL IOWA...
  SOUTHWESTERN POLK COUNTY IN CENTRAL IOWA...

* UNTIL 730 PM CST

* AT 144 PM CST...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH   
FLOODING ACROSS THE WARNED AREA. ICE JAMMING WAS OCCURRING AT THE 
WALK BRIDGE IN THE DES MOINES WATER WORKS.  THE RIVER GAGE AT 63RD 
STREET INDICATED THAT WATER WAS BEGINNING TO OVERFLOW THE BANKS OF 
THE RIVER.  AT PRESENT...THE ICE JAM WAS NOT MOVING.  THIS WILL 
RESULT IN UPSTREAM FLOODING FROM WATERWORKS PARK.  THE JAM IS LIKELY 
TO BREAK LATER THIS AFTERNOON...SENDING A SURGE OF WATER DOWN THE 
RACCOON RIVER TO THE MOUTH AT THE DES MOINES RIVER.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...DES
  MOINES...PLEASANT HILL AND WEST DES MOINES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOOD WATERS WILL MOVE DOWN THE RACCOON RIVER FROM UPSTREAM OF 
WATERWORKS PARK DOWNSTREAM TOWARD THE DES MOINES RIVER.

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. TURN AROUND...DONT DROWN.

&&

LAT...LON 4156 9389 4164 9355 4152 9346 4150 9388
      4151 9389

$$
3 follow-up statements
027 
WGUS73 KDMX 172051
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
251 PM CST THU FEB 17 2011

IAC049-153-180130-
/O.CON.KDMX.FF.W.0001.000000T0000Z-110218T0130Z/
/00000.0.IJ.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POLK IA-DALLAS IA-
251 PM CST THU FEB 17 2011

...FLASH FLOOD WARNING FOR ICE JAM FLOODING REMAINS IN EFFECT FOR
SOUTHEASTERN DALLAS AND SOUTHWESTERN POLK COUNTIES UNTIL 730 PM
CST...

AT 247 PM CST...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED THAT FLASH 
FLOODING WAS OCCURRING IN THE RACCOON RIVER DUE TO ICE JAMMING.  THE 
EXTENT OF THE BACKUP IS FROM THE WALK BRIDGE IN WATERWORKS 
PARK...WEST TO ABOUT A MILE WEST OF THE DALLAS-POLK COUNTY LINE.  
THE RIVER GAGE ON HIGHWAY 28 INDICATED A RISE OF 9 FEET EARLY THIS 
AFTERNOON TO JUST OVER 34 FEET. IN THE PAST HOUR IT HAS FALLEN 4 
FEET TO JUST OVER 30 FEET...2 FEET BELOW FLOOD STAGE.  THIS 
INDICATES THE ICE JAM MAY BE BEGINNING TO MOVE DOWNSTREAM ONCE AGAIN.

SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...DES
MOINES...PLEASANT HILL AND WEST DES MOINES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR AND THE
WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. TURN
AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLASH FLOODING IS IMMINENT OR
OCCURRING. IF YOU ARE IN THE WARNING AREA...MOVE TO HIGHER GROUND
IMMEDIATELY. RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE
IMMEDIATE PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO
CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 4156 9389 4164 9355 4152 9346 4150 9388
      4151 9389

$$
924 
WGUS73 KDMX 172158
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
358 PM CST THU FEB 17 2011

IAC049-153-180130-
/O.CON.KDMX.FF.W.0001.000000T0000Z-110218T0130Z/
/00000.0.IJ.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POLK IA-DALLAS IA-
358 PM CST THU FEB 17 2011

...FLASH FLOOD WARNING FOR ICE JAM FLOODING REMAINS IN EFFECT FOR
SOUTHEASTERN DALLAS AND SOUTHWESTERN POLK COUNTIES UNTIL 730 PM
CST...

AT 355 PM CST...ICE JAMMING WAS REPORTED ON THE RACCOON RIVER FROM 
ABOUT A MILE WEST OF THE DALLAS-POLK COUNTY LINE...DOWNSTREAM TO 
FLEUR DRIVE.

SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...DES 
MOINES...PLEASANT HILL AND WEST DES MOINES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE RACCOON RIVER WAS FLUCTUATING RAPIDLY DUE TO ICE ACTION.  THE 
RIVER GAGE AT HIGHWAY 28 RISE 9 FEET...TO ABOUT 2 FEET ABOVE FLOOD 
STAGE EARLIER THIS AFTERNOON AS THE ICE JAM MOVED THROUGH THAT AREA. 
THE RIVER STATE AT FLEUR DRIVE HAS RISEN ABOUT 5 FEET BY 330 PM.  


FLUCTUATIONS IN RIVER LEVELS WILL CONTINUE THROUGH THE NEXT SEVERAL 
HOURS...WITH OCCASIONAL BREACHES OF THE RIVER BANK AS THE ICE HANGS 
UP.  

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR AND THE
WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. TURN
AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLASH FLOODING IS IMMINENT OR
OCCURRING. IF YOU ARE IN THE WARNING AREA...MOVE TO HIGHER GROUND
IMMEDIATELY. RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE
IMMEDIATE PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO
CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 4156 9389 4164 9355 4152 9346 4150 9388
      4151 9389

$$
778 
WGUS73 KDMX 172344
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
544 PM CST THU FEB 17 2011

IAC049-153-172355-
/O.CAN.KDMX.FF.W.0001.000000T0000Z-110218T0130Z/
/00000.0.IJ.000000T0000Z.000000T0000Z.000000T0000Z.OO/
POLK IA-DALLAS IA-
544 PM CST THU FEB 17 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHEASTERN DALLAS
AND SOUTHWESTERN POLK COUNTIES IS CANCELLED...

THE ICE JAM HAS CONTINUED TO MOVE DOWNSTREAM THROUGH THE LOWER 
RACCOON RIVER CHANNEL. RIVER LEVELS HAVE RETURNED TO WITHIN THE  
BANKS ALONG THE RACCOON RIVER IN SOUTHEAST DALLAS COUNTY AND POLK 
COUNTY...THEREFORE THE WARNING HAS BEEN CANCELLED.  ADDITIONAL 
FLUCTUATIONS IN RIVER LEVELS WILL BE POSSIBLE THIS EVENING AS ICE 
CONTINUES TO MOVE THROUGH THE CHANNEL.  THOSE WITH INTEREST ALONG 
THE LOWER RACCOON RIVER SHOULD CONTINUE TO MONITOR FOR ANY RAPID 
FLUCTUATIONS ALONG THE RIVER AND BE PREPARED TO TAKE QUICK ACTION IF 
NECESSARY.  

LAT...LON 4156 9389 4164 9355 4152 9346 4150 9388
      4151 9389

$$

COGIL

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 16, 6:00 PM CSTDense Fog AdvisoryDMXAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more16 hr

Nearby

Flash Flood Warnings in Iowa, 2011Every flash flood warning in 2011

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.