Alert archive / Iowa / Flash Flood Warnings in 2011

Flash Flood Warning 33, NWS Des Moines, IA

July 16, 2011Cass County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 16, 2011, 2:22 AM CDT for Cass County, Iowa. It was in force for 6 hr. 2 reports 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 16, 2011, 2:22 AM CDT (07:22 UTC)
Expired: Jul 16, 2011, 8:30 AM CDT
In force: 6 hr
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Flood severity: None

County Cass County, IA

The radar

The Omaha radar (KOAX), 109 km from the middle of the area, began a volume at 07:23 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 16, 3:09 AM CDT	HEAVY RAIN 3.32	1 Ne Atlantic, IA	COOPERATIVE OBSERVER IN ATLANTIC MEASURED 3.32 INCHES OF RAIN FROM OVERNIGHT STORMS. IT RAINED FOR A LITTLE OVER TWO HOURS BUT HE ESTIMATES MOST OF THE TOTAL FELL IN ABOUT AN HOUR. ALSO REPORTED MINOR FLOODING OF STREETS AND LOW LYING AREAS THROUGHOUT ATLANTIC
Jul 16, 7:12 AM CDT	HEAVY RAIN 3.5	Atlantic, IA	MEASURED RAINFALL SINCE MIDNIGHT.

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, 7.4 hours before the alert went out and 109 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: 6222 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 837 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 156 m²/s²
0-3 km storm-relative helicity: 295 m²/s²
Significant tornado parameter: 5.2
Supercell composite: 27.3

Open this sounding in Storm Lab

The text

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

498 
WGUS53 KDMX 160722
FFWDMX
IAC029-161330-
/O.NEW.KDMX.FF.W.0033.110716T0722Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
222 AM CDT SAT JUL 16 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN CASS COUNTY IN SOUTHWEST IOWA...

* UNTIL 830 AM CDT

* AT 221 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED  
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE  
  WARNED AREA. RADAR ESTIMATES THAT UP TO 3 INCHES OF RAIN HAS 
  FALLEN IN PARTS OF THE AREA IN THE PAST COUPLE OF HOURS...AND 
  HEAVY RAIN WILL CONTINUE FOR SOME TIME.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE 
WARNED AREA.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. DO
NOT ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND TO
ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN
WATER BEGINS RISING.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN DES
MOINES.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

6 follow-up statements

306 
WGUS73 KDMX 160832
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
332 AM CDT SAT JUL 16 2011

IAC029-161330-
/O.CON.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
332 AM CDT SAT JUL 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 830 AM CDT...

AT 331 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THUNDERSTORMS HAVE FINALLY ENDED ACROSS THE WARNED AREA. A 
TRAINED SPOTTER IN ATLANTIC REPORTED 3.32 INCHES OF RAINFALL FROM 
THE STORMS...AND RADAR INDICATES THAT HIGHER AMOUNTS FELL TO THE 
NORTHWEST AROUND MARNE.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH  FLOODING INCLUDE...
ATLANTIC.

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 ALSO SUBJECT TO FLOODING.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

906 
WGUS73 KDMX 160941
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
441 AM CDT SAT JUL 16 2011

IAC029-161330-
/O.CON.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
441 AM CDT SAT JUL 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 830 AM CDT...

AT 441 AM CDT...NATIONAL WEATHER SERVICE RADAR AND TRAINED SPOTTERS 
INDICATED THAT 3 TO 4 INCHES OF RAIN FELL ACROSS PORTIONS OF THE 
WARNING AREA DURING THUNDERSTORMS EARLY THIS MORNING. RUNOFF FROM 
THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO OCCUR. SOME 
LOCATIONS THAT WILL EXPERIENCE FLASH FLOODING INCLUDE...ATLANTIC.

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 ALSO SUBJECT TO FLOODING.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

782 
WGUS73 KDMX 161034
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
534 AM CDT SAT JUL 16 2011

IAC029-161330-
/O.CON.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
534 AM CDT SAT JUL 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 830 AM CDT...

AT 534 AM CDT...NATIONAL WEATHER SERVICE RADAR AND TRAINED SPOTTERS 
INDICATED THAT 3 TO 5 INCHES OF RAIN FELL ACROSS PARTS OF THE WARNED 
AREA DURING HEAVY THUNDERSTORMS EARLIER THIS MORNING. THE STORMS 
HAVE ENDED...BUT RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE 
FLASH FLOODING TO OCCUR. SOME LOCATIONS THAT MAY EXPERIENCE FLASH  
FLOODING INCLUDE...ATLANTIC.

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 ALSO SUBJECT TO FLOODING.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

546 
WGUS73 KDMX 161129
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
629 AM CDT SAT JUL 16 2011

IAC029-161330-
/O.CON.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
629 AM CDT SAT JUL 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 830 AM CDT...

AT 629 AM CDT...NATIONAL WEATHER SERVICE RADAR AND TRAINED SPOTTERS 
INDICATED THAT 3 TO 5 INCHES OF RAIN FELL IN PARTS OF THE WARNED 
AREA IN LESS THAN TWO HOURS EARLIER THIS MORNING.

SOME LOCATIONS THAT MAY EXPERIENCE FLASH FLOODING INCLUDE...ATLANTIC.

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 ALSO SUBJECT TO FLOODING.

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.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

472 
WGUS73 KDMX 161224
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
724 AM CDT SAT JUL 16 2011

IAC029-161330-
/O.CON.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
724 AM CDT SAT JUL 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR NORTHWESTERN CASS COUNTY
UNTIL 830 AM CDT...

AT 723 AM CDT...WEATHER SPOTTERS AND NATIONAL WEATHER SERVICE RADAR 
INDICATED THAT 3 TO 5 INCHES OF RAIN FELL IN A SHORT TIME ACROSS THE 
WARNED AREA EARLIER THIS MORNING.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. SOME LOCATIONS THAT MAY EXPERIENCE FLASH FLOODING 
INCLUDE...ATLANTIC.

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 ALSO SUBJECT TO FLOODING.

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.

&&

LAT...LON 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

LEE

676 
WGUS73 KDMX 161325
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
825 AM CDT SAT JUL 16 2011

IAC029-161340-
/O.EXP.KDMX.FF.W.0033.000000T0000Z-110716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS IA-
825 AM CDT SAT JUL 16 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR NORTHWESTERN
CASS COUNTY WILL BE ALLOWED TO EXPIRE AT 830 AM CDT...

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 4151 9516 4151 9504 4150 9496 4138 9498
      4136 9516

$$

BEERENDS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 15, 7:20 PM CDT	Flash Flood Warning	DMX	Cerro Gordo, Worth	4 hr
Jul 15, 9:15 PM CDT	River Flood Warning	DMX	Black Hawk	6 days
Jul 15, 9:15 PM CDT	River Flood Warning	DMX	Black Hawk	5 days
Jul 15, 9:15 PM CDT	River Flood Warning	DMX	Black Hawk, Bremer, Butler	5 days
Jul 15, 11:25 PM CDT	Areal Flood Warning	DMX	Cerro Gordo, Worth	24 hr

Nearby

Flash Flood Warnings in Iowa, 2011 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.