Flash Flood in Iowa, June 4, 2002

Name: Flash Flood in Iowa, June 4, 2002
Start: 2002-06-04T04:20
End: 2002-06-04T05:30
Location: Iowa

June 4, 2002 · NWS ARX · 1 event in 1 county or zone

Flash flooding was caused by 4 to 5 inches of rain in 1 to 2 hours, which resulted in extensive damage to roads, bridges and farm fields. Hardest hit were areas from Edgewood toward Millville.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: $350,000
Crop damage: $125,000
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS ARX wrote it up.

Flash flooding was caused by 4 to 5 inches of rain in 1 to 2 hours, which resulted in extensive damage to roads, bridges and farm fields. Hardest hit were areas from Edgewood toward Millville. As a result, Clayton County was declared a federal disaster area, along with several other eastern Iowa counties.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS La Crosse, WI wrote its last area forecast discussion before the first event at Jun 4, 2:19 AM CST, 2 hours 1 minute earlier.

Area forecast discussion, Jun 4, 2:19 AM CST, 2 hours 1 minute before

AREA FORECAST DISCUSSION...UPDATED...CORRECTED.
NATIONAL WEATHER SERVICE LA CROSSE WI
319 AM CDT TUE JUN 4 2002

*****UPDATED*****
LATEST DATA ANALYSIS AT 08Z SHOWS WIDESPREAD HEAVY RAINFALL OVER
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. CORFIDI VECTORS AND STRONG
LOW-MID LEVEL FORCING SUGGESTS RAINFALL CONTINUING ACROSS THE SAME
AREA THROUGH MID-LATE MORNING.  THEN...THE FORCING FROM THE UPPER
LEVEL DISTURBANCE EXPECTED TO PASS TO THE NORTH WILL INDUCE MORE
THUNDERSTORMS ACROSS THE SAME AREA LATER TODAY.  AS A RESULT...HAVE
ISSUED A FLOOD WATCH FOR THIS AREA.
*****************

MAIN FORECAST FOCUS IS ON RAIN CHANCES THROUGH MIDWEEK.

SUBJECTIVE DATA ANALYSIS AT 04Z SHOWING THE SAME STALLED BOUNDARY
MEANDERING ACROSS SOUTHERN IOWA.  A WEAK DISTURBANCE ALONG THE FRONT
IS LOCATED IN SOUTHWESTERN IOWA.  CONVECTION HAS BEEN DEVELOPING
ACROSS THE FORECAST AREA...THE RESULT OF INCREASING LOW LEVEL FLOW
OVER THE WARM FRONT.  HEAVY RAIN AT THIS TIME IS FURTHER SOUTH THAN
LAST NIGHTS STORMS.  SATURATED SOILS FROM LAST NIGHTS STORMS ARE
MAINLY IN SOUTHEAST MINNESOTA AND FROM LA CROSSE NORTH AND EAST.

EXPECT CONVECTION TO CONTINUE TO DEVELOP AND BECOME ORGANIZED INTO
AN MCS.  CORFIDI VECTORS SUGGEST SOMEWHAT SLOW PROPAGATION.  THIS IN
CONJUNCTION WITH THE AFOREMENTIONED SATURATED SOILS SPELLS TROUBLE
FOR FLOODING.  WILL BE MONITORED FOR A WATCH THIS MORNING.

LARGER SCALE SHOWS AN UPPER LEVEL DISTURBANCE MOVING INTO NORTHERN
MONTANA.  THIS WILL BE THE UPPER LEVEL FEATURE THAT WILL USHER THE
BOUNDARY TO THE SOUTH.

THE CONVECTION SHOULD MOVE OUT THIS MORNING.  THERE SHOULD BE A
BRIEF RESPITE FROM THE PRECIPITATION UNTIL THE LARGE SCALE FORCING
FROM THE APPROACHING UPPER LEVEL DISTURBANCE NEARS THE FORECAST AREA
LATER IN THE DAY.  THE EXCEPTION WILL BE OVER THE SOUTHERN
ZONES WHERE ONCE AGAIN THE FORCING REMAINS FOCUSED ALONG
THE FRONT.  THIS DID CAUSE SOME REDEVELOPMENT DURING THE DAY TODAY
AND SEE NO REASON WHY THIS WILL NOT HAPPEN AGAIN.  WILL WAIT UNTIL
ISSUANCE TO MAKE FINAL DECISION ON THIS GIVEN CURRENT DATA AT THAT
TIME.

UPPER LEVEL FORCING THIS EVENING...WHICH IS QUITE STRONG...REMAINS
FOCUSED TO THE NORTH WHERE THE DISTURBANCE IS.  LOW LEVEL FORCING IS
FOCUSED ALONG THE FRONT WHERE ONE MIGHT EXPECT IT.  THESE MOVE
THROUGH THE REGION...BRINGING MORE THUNDERSTORMS TO THE FORECAST
AREA.  TIMING IS DIFFICULT...BUT GIVEN THE CURRENT LOCATION...THINK
THERE WILL BE A BREAK FROM THE CONVECTION THIS MORNING...THEN ANOTHER
ROUND OF CONVECTION THIS EVENING.

THE DISTURBANCE PUSHES THE FRONT SOUTH...AS HIGH PRESSURE BUILDS INTO
THE FORECAST AREA AND REMAINS THROUGH WEDNESDAY NIGHT.  THE UPPER
LEVEL COLD POOL WILL MOVE THROUGH WEDNESDAY.  TQ INDEX SUGGESTS
CLOUDS DURING THE DAY...WITH SOME SHOWERS POSSIBLE.

NEXT SYSTEM TO AFFECT THE REGION WILL DROP OUT OF CANADA THURSDAY.
AHEAD OF THIS SYSTEM...SOUTHWESTERLY WINDS WILL DEVELOP.  THIS WILL
TRANSPORT WARMER AIR INTO THE REGION.

.LSE...FLOOD WATCH THROUGH 4 PM TODAY...IAZ010-011-029-030-
       WIZ054>056.

KRC

In the hours before

Local storm report, Jun 4, 12:50 AM CST, 3 hours 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
150 AM CDT TUE JUN 4 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0115 AM    ROCHESTER                 MN   .75 INCH HAIL
06/04/02   OLMSTED                        REPORTED BY KTTC-TV

0115 AM    ROCHESTER                 MN   1 INCH HAIL
06/04/02   OLMSTED                        REPORTED BY PUBLIC

JR

The radar

The La Crosse radar (KARX), 109 km away, was scanning. The volume nearest the first event began at 10:20 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Clayton

When: June 4, 4:20 AM CST to 5:30 AM CST
Where: Clayton County, South Portion
Property damage: $350,000
Crop damage: $125,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.845, -91.341 (the zone’s center; the record gives no point)

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 2002 Every state in 2002 This day in weather history Warnings in Iowa, June 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5305718.