Flash Flooding in Wisconsin, May 8 to 9, 2002

Name: Flash Flooding in Wisconsin, May 8 to 9, 2002
Start: 2002-05-08T20:15
End: 2002-05-09T01:00
Location: Wisconsin

May 8 to 9, 2002 · NWS ARX · 4 events in 2 counties and zones

Rainfall totals of 4 inches in an hour produced flash flooding, including mud and rock slides. Several road washouts occurred, along with reports of flooded basements.

Where it happened

Every event with a place to put it; 4 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $14,000
Crop damage: None recorded
Events: 4

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.

Rainfall totals of 4 inches in an hour produced flash flooding, including mud and rock slides. Several road washouts occurred, along with reports of flooded basements.

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 May 8, 2:32 PM CST, 5 hours 43 minutes earlier.

Area forecast discussion, May 8, 2:32 PM CST, 5 hours 43 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
332 PM CDT WED MAY 8 2002

...SEVERE WEATHER THREAT ACROSS MUCH OF THE AREA TONIGHT...

THE MAIN FORECAST CONCERN WITH THIS PACKAGE DEALS WITH THE SEVERE WEATHER
THREAT FOR TONIGHT...AND STRONG WINDS FOR THURSDAY.

AT 3 PM...A STRENGTHENING SURFACE LOW WAS LOCATED OVER NORTHWEST IOWA.
BOTH THE ETA AND AVN MODELS HAVE THIS LOW POORLY INITIALIZED. THEY TEND
TO DEVELOP THE LOW OVER KANSAS AS THE MAIN LOW AND IGNORE THIS LOW.
HOWEVER...LOOKING AT THE SURFACE DEW POINTS...THE NORTHERN LOW WILL BE
THE MORE SIGNIFICANT OF THESE LOW PRESSURE AREAS. BY LOOKING AT THE
SURFACE DEW POINTS IT WOULD SUGGEST THAT THIS LOW WILL TRACK TOWARD
THE TWIN CITIES THIS EVENING. BREEZY SOUTH AND SOUTHEAST WINDS
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST
WISCONSIN HAVE INCREASED THE SURFACE DEW POINTS INTO THE UPPER 50S
AND LOWER 60S. IN ADDITION...SUNSHINE THIS AFTERNOON HAS CAUSED
TEMPERATURES TO CLIMB INTO THE MIDDLE 70S ACROSS SOUTHEAST MINNESOTA
AND AROUND 80 IN NORTHEAST IOWA. SATELLITE SOUNDER DATA INDICATES
THAT THE LIFTED INDICES HAVE FALLEN TO -8 OVER NORTH CENTRAL IOWA AND
THE CAPES HAVE INCREASED TO AROUND 1500 J/KG ACROSS NORTHEAST IOWA.
FROM LOOKING AT THE BLUE RIVER PROFILER...THERE IS PLENTY OF SPEED
AND DIRECTIONAL SHEAR. AS A RESULT...I EXPECT THE THUNDERSTORMS TO
FORM INITIALLY AS SUPERCELLS AND EVENTUALLY EVOLVE INTO A SQUALL
LINE THIS EVENING. THE INITIAL THREAT OF SEVERE WEATHER APPEARS TO
BE LARGE HAIL AND POTENTIALLY SOME ISOLATED TORNADOES...AND THEN
EVOLVE INTO A DAMAGING WIND EVENT.

AS THE LOW CONTINUES TO STRENGTHEN DURING THE DAY THURSDAY...THE
PRESSURE GRADIENT WILL CONTINUE TO INCREASE ACROSS THE COUNTY
WARNING AREA. IN ADDITION...THE AREA WILL SEE STRONG SUBSIDENCE
BEHIND THE SHORT WAVE. THE 1000 MB TO 850 MB LAPSE RATES ARE
MARGINAL FOR ADVECTING THE REALLY STRONG WINDS FROM ALOFT TO THE
SURFACE. AS A RESULT...THE WINDS WILL NOT BE QUITE AS STRONG AS THEY
COULD GET. HOWEVER...THE SUSTAINED WIND SPEEDS WILL LIKELY STILL BE
IN THE 25 TO 35 MPH RANGE IN SOUTHEAST MINNESOTA AND NORTHEAST
IOWA...AND IN THE 20 TO 30 MPH RANGE ACROSS THE REMAINDER OF THE
AREA. WIND GUSTS WILL BE LIKELY AROUND 45 MPH. CONSIDERING ALL THAT
IS GOING ON TONIGHT...I DIDNT ISSUE A WIND ADVISORY AT THIS TIME...
BUT ONE MAY BE NEEDED FOR THURSDAY IF THE LAPSE RATES GET ANY
STEEPER.

.LSE...NONE.

BOYNE

In the hours before

Local storm report, May 8, 6:48 PM CST, 1 hour 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
748 PM CDT WED MAY 8 2002

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

0746 PM    3 SE CALMAR               IA   TORNADO
05/08/02   WINNESHIEK                     REPORTED ALONG HIGHWAY 52
                                          BETWEEN OSSIAN AND CALMAR
                                          BY STORM CHASERS.

SHEA

Local storm report, May 8, 6:52 PM CST, 1 hour 23 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
752 PM CDT WED MAY 8 2002

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

0704 PM    PROTIVIN                  IA   70 MPH WIND GUST
05/08/02   HOWARD                         REPORTED BY COUNTY SHERIFF.
                                          NICKEL SIZE HAIL ALSO FELL.
                                          SOME WATER PONDING. DAMAGE
                                          MAY HAVE BEEN ON CHICKASAW
                                          COUNTY SIDE.

SHEA

Local storm report, May 8, 7:21 PM CST, 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
821 PM CDT WED MAY 8 2002

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

0816 PM    WAUKON                    IA   71 MPH WIND GUST
05/08/02   ALLAMAKEE                      REPORTED BY SCHOOLNET VIA
                                          KWWL TV. WIND DIRECTION WAS
                                          SOUTHWEST.

SHEA

Local storm report, May 8, 7:22 PM CST, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
822 PM CDT WED MAY 8 2002

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

0815 PM    WAUKON                    IA   FUNNEL CLOUD
05/08/02   ALLAMAKEE                      SWIRLING CLOUDS NOTED BY
                                          SHERIFF DEPT.

SHEA

Local storm report, May 8, 7:30 PM CST, 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
830 PM CDT WED MAY 8 2002

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

0810 PM    2 W WAUKON                IA   WIND DAMAGE
05/08/02   ALLAMAKEE                      UBC LUMBER HAD DAMAGE TO
                                          BUILDINGS.

SHEA

Local storm report, May 8, 8:10 PM CST, 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
910 PM CDT WED MAY 8 2002

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

0857 PM    4 E EASTMAN               WI   60 MPH WIND GUST
05/08/02   CRAWFORD                       REPORTED BY THE PUBLIC.
                                          GUST SPEED ESTIMATED.

SHEA

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

4 flash flood. Local standard time, as filed.

Flash Flood, Crawford

When: May 8, 8:15 PM CST to 10:30 PM CST
Where: Crawford County, 6 mi NE of Mt Sterling
Property damage: $3,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.240, -90.931 (the zone’s center; the record gives no point)

Flash Flood, Crawford

When: May 8, 9:15 PM CST to 10:50 PM CST
Where: Crawford County, Gays Mills
Property damage: $3,000
Reported by: GENERAL PUBLIC
Coordinates: 43.240, -90.931 (the zone’s center; the record gives no point)

Flash Flood, Crawford

When: May 8, 9:30 PM CST to 10:45 PM CST
Where: Crawford County, 3 mi N of Lynxville
Property damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.240, -90.931 (the zone’s center; the record gives no point)

Flash Flood, Richland

When: May 8, 9:35 PM CST to May 9, 1:00 AM CST
Where: Richland County, 4 mi W of Richland Center
Property damage: $4,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.376, -90.429 (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 Wisconsin in 2002 Every state in 2002 This day in weather history Warnings in Wisconsin, May 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: 5294375, 5294376, 5294378, 5294377.