Alert archive / Iowa / Flash Flood Warnings in 1997

Flash Flood Warning 1, NWS Des Moines, IA

February 19, 1997Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Feb 19, 1997, 10:07 PM CST for Polk County, Iowa. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 19, 1997, 10:07 PM CST (04:07 UTC)
Expired
Feb 20, 1997, 3:05 AM CST
In force
5 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk County, IA

The radar

The Des Moines radar (KDMX), 13 km from the middle of the area, began a volume at 04:10 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 00:00Z, 4.1 hours before the alert went out and 236 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 00:00Z on 1997-02-20Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 1997-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 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
1689 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
169 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 
TTAA00 KDSM 200407
FFWDSM
IAC153-200905-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1007 PM CST WED FEB 19 1997

* FLASH FLOOD WARNING FOR
  SOUTHERN POLK COUNTY - CENTRAL IOWA

* UNTIL 305 AM CST
 
* SOME STREAMS AFFECTED
    THE LOWER REACHES OF THE RACOON RIVER

* CAUSE AND EFFECT
    DURING THE EVENING AN ICE JAM FORMED AT THE 63RD STREET BRIDGE
    ON THE RACCOON RIVER.  THE ICE JAM HAS BROKEN AND RAPID RISES
    WILL OCCUR ALONG THE LOWER REACHES OF THE RIVER.  THE WATER WILL
    CAUSE SIGNIFICANT FLOODING IN THE LOW LANDS OF WATERWORKS PARK.
    SOUTHWEST 3OTH STREET MAY BRIEFLY BECOME FLOODED.

* FORECAST CONDITIONS
    THE RIVER HAD RISEN SHARPLY AND AT 1000 PM WAS AT 13.46 FEET.
    FLOOD STAGE IS 12 FEET.  THE RIVER WILL CREST NEAR 14 FEET.
    FLUCTUATIONS OF 1 TO 2 FEET ARE EXPECTED DURING THE NEXT
    SEVERAL HOURS UNTIL THE ICE PASSES THROUGH DES MOINES.

LEAVE FLOOD PRONE OR LOW LYINBG AREAS IMMEDIATELY.
 

&

Nearby

Flash Flood Warnings in Iowa, 1997Every flash flood warning in 1997

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.