Thunderstorms continuously redeveloped in an east-west band across Northeast Iowa and Northwest Illinois producing extremely heavy rainfall and flash flooding. 69 inches).
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS DVN wrote it up.
Thunderstorms continuously redeveloped in an east-west band across Northeast Iowa and Northwest Illinois producing extremely heavy rainfall and flash flooding. The heaviest rainfall occurred from Durango, Iowa (6.25 inches) to Galena, Illinois (11.69 inches). More than 9 inches of rain fell in parts of Dubuque County. Numerous roads were closed in mostly low lying areas. A few homes were also flooded.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Aug 21, 12:51 PM CST, 12 hours 9 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 151 PM CDT WED AUG 21 2002 SYNOPSIS... MORNING UA AND SURFACE ANALISIS SHOWS THE AREA IS NOW IN THE WARM AND MOIST SECTOR. THE SURFACE WARM FRONT AT 15Z EXTENDS FROM NEAR FSD TO ALO TO VYS. WELL DEFINED SHORT WAVE JUST WEST OF MCI AT 12Z...NOW APPROACHING THE UPPER MIDWEST FROM THE SOUTHWEST. THIS WAVE HAS SPAWNED OVERNIGHT CONVECTION FROM KANSAS THROUGH NORTHWEST IOWA. MUCH OF THIS IS NOW DECAYING AS EXPECTED...WITH THE EXCEPTION OF PORTION NEAR MCI. THIS WILL BE THE CONVECTIVE CLUSTER TO WATCH AS IT APPROACHES THE CWA THIS AFTERNOON. CIRRUS AND DEBRIS CLOUDS CONTINUE TO SLOWLY THIN NORTH OF INTERSTATE 80...WITH MODERATED INSOLATION ALREADY IN PLACE SOUTH OF THE INTERSTATE. THIS WILL ALLOW ADEQUATE HEATING FOR STORMS TO INTENSIFY IN OUR AREA THIS AFTERNOON. SHORT TERM... SEVERE WEATHER THREAT WILL MAINLY AFFECT THE AREA THIS EVENING...WITH HEAVY RAIN EXPECTED LATE EVENING AND OVERNIGHT. PWAT VALUES IN EXCESS OF TWO INCHES NOTED ON THE OMA 12Z SOUNDING AND NEAR 2 INCHES ON 18Z DVN SOUNDING...SHOW TROPICAL AIRMASS OVER THE REGION. DESPITE MODEL DIFFERENCES...ALL SHORT TERM MODELS INDICATE DIFFLUENT THICKNESS OVER THE CWA TONIGHT THROUGH THURSDAY MORNING. TRAINING CELLS APPEAR TO BE LIKELY GIVEN NEARY STATIONARY BOUNDARY OVER THE CWA. ALL THIS SAID... COUNTY FFG GUIDANCE VALUES ARE RUNNING RATHER HIGH AND CROPS ARE MATURE. THEREFORE I FEEL WIDESPREAD FLOODING PROBLEMS DO NOT WARRANT A FLOOD WATCH AT THIS TIME. URBAN FLOODING MAY BECOME AN ISSUE...IF STORMS PICK ON ONE AREA REPEATEDLY. THE FRONT BECOMES QUASI-STATIONARY THURSDAY AND FRIDAY...WITH SEVERAL ROUNDS OF HEAVY RAIN AND THUNDESTORMS EXPECTED THROUGH FRIDAY NIGHT. IF HEAVY RAIN DOES MATERIALIZE TONIGHT...A FLOOD WATCH MAY BE NEEDED FOR THURSDAY NIGHT AND FRIDAY FOR AREAS THAT RECIEVE HEAVY RAIN TONIGHT. EXTENDED... NO MAJOR CHANGES EXPECTED IN EXTENDED AS CANADIAN HIGH SETTLES SOUTH ACROSS THE AREA FOR SEVERAL DAYS OF PLEASANT WEATHER. MRF AND UKMET CONTINUE TO INDICATE A LOBE UPPER LEVEL VORTICITY WORKING SOUTH ACROSS THE AREA MONDAY. FOR NOW...I WILL NOT CHANGES THE GOING FORECAST...BUT SHOWERS MAY NEED TO BE ADDED IF THIS FEATURE MOVES OVER THE AREA DURING PEAK HEATING. OTHERWISE...DRY WEATHER WILL CONTINUE THROUGH WEDNESDAY...WITH SLOWLY MODERATING TEMPERATURES. .DVN... IA...NONE. IL...NONE. MO...NONE. ERVIN/DVN LAST/OMA NEXT
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1011 PM CDT WED AUG 21 2002
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0944 PM (DBQ)DUBUQUE MUNI ARPT IA 64 MPH TSTM GUST
08/21/02 DUBUQUEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1110 PM CDT WED AUG 21 2002
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1105 PM INDEPENDENCE IA FLOOD
08/21/02 BUCHANAN STREETS FLOODED.
REPORTED BY STORM
SPOTTER.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1201 AM CDT THU AUG 22 2002
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
1156 PM DUBUQUE ARPT IA FLOOD
08/21/02 DUBUQUE AUTOMATED SURFACE
OBSERVING SYSTEM (ASOS)
MEASURED 4.4 INCHES IN
THE PAST 3 HOURS.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
132 AM CDT THU AUG 22 2002
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0100 AM 3 N STOCKTON IL FLOOD
08/22/02 JO DAVIESS BASEMENT OF HOUSE
FLOODED. REPORTED BY
STORM SPOTTER.The Quad Cities radar (KDVN), 116 km away, was scanning. The volume nearest the first event began at 07:01 UTC.
5 flash flood. Local standard time, as filed.
Rural road washed out and inundated with debris.
Significant street flooding.
Water up to 3 feet deep forced the evacuation of Swiss Valley Campground.
Spring Valley trailer park evacuated due to high water up to 3 feet deep.
Numerous streets inundated with high water and debris.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2002Every state in 2002This day in weather historyWarnings in Iowa, August 2002
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: 5312857, 5312858, 5312859, 5312860, 5312918.