Thunderstorms developed ahead of a cold front and tracked across western Wisconsin during the evening of August 30th. These thunderstorms produced some wind damage and a mudslide east of Alma (Buffalo County).
Every event with a place to put it. 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 ARX wrote it up.
Thunderstorms developed ahead of a cold front and tracked across western Wisconsin during the evening of August 30th. These thunderstorms produced some wind damage and a mudslide east of Alma (Buffalo County).
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 Aug 31, 1:23 PM CST, 5 hours 59 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 223 PM CDT TUE AUG 31 2010 .SHORT TERM...THROUGH THURSDAY NIGHT MAIN FORECAST CONCERNS ARE WITH THE RAIN CHANCES THROUGH THE PERIOD. SURFACE ANALYSIS THIS AFTERNOON SHOWS A COLD FRONT EXTENDING FROM NORTH CENTRAL MINNESOTA INTO EASTERN NEBRASKA. LOCAL AND REGIONAL RADARS SHOWS A BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM NORTHEAST WISCONSIN INTO EASTERN IOWA. ONLY WIDELY SCATTERED ACTIVITY ALONG THE FRONT ACROSS SOUTHWEST MINNESOTA INTO NORTHWEST IOWA. EXPECTING THE LEADING BAND OF SHOWERS AND THUNDERSTORMS TO BE EXITING OUT OF THE AREA BY 00Z OR SHORTLY THERE AFTER. THE CONCERN THEN BECOMES HOW MUCH ACTIVITY WILL DEVELOP ALONG THE FRONT THROUGH THE REMAINDER OF THE AFTERNOON INTO THE EVENING. THE MAIN SHORT WAVE TROUGH WILL BE LIFTING NORTHEAST ACROSS THE DAKOTAS INTO SOUTHERN CANADA TAKING THE BEST PV ADVECTION IN THE 500-300 MB LAYER WELL TO THE NORTHWEST OF THE FORECAST AREA. THE LOW LEVEL FORCING ALONG THE FRONT WILL BE SUPPORTED BY WEAK FRONTOGENESIS IN THE 1000-700 MB LAYER...WEAK FN VECTOR CONVERGENCE IN THE 1000-850 MB LAYER AND WEAK SURFACE MOISTURE CONVERGENCE ALONG THE FRONT. THE MOISTURE TRANSPORT AT 850 MB IS EXPECTED TO INCREASE THROUGH THE AFTERNOON INTO THE EVENING AHEAD OF THE SHORT WAVE TROUGH AND INTERSECT THE FRONT ACROSS MAINLY IOWA AND THEN TURN NORTHEAST WITH THE AREA ON THE WESTERN GRADIENT OF THE TRANSPORT AREA. OVERALL...DOES NOT SEEM TO BE A LOT OF SUPPORT FOR WIDESPREAD DEVELOPMENT ALONG THE FRONT YET THE 31.12Z NAM AND GFS SHOW ACTIVITY BLOSSOMING ALONG THE FRONT. THE 31.12Z SPC WRF SEEMS TO FOCUS MORE ACROSS IOWA WHERE THE MOISTURE TRANSPORT IS BETTER WHILE THE RAPID UPDATES OF THE RUC MAINLY SHOW SCATTERED ACTIVITY ALONG THE ENTIRE FRONT AS IT COMES THROUGH. WITH THE SYSTEM NOT SHOWING ITS HAND YET AS TO WHAT WILL HAPPEN HAVE BEEN CONSERVATIVE WITH CHANGES FOR TONIGHT. ATTEMPTED TO DETAIL THE RAIN CHANCES EARLY THIS EVENING FOCUSING ON THE CURRENT LINE EXITING OUT TO THE EAST WITH THE ACTIVITY ALONG THE FRONT MAINLY AFFECTING THE WEST WITH LOWER RAIN CHANCES IN BETWEEN. THEN MAINTAINED THE 70 TO 80 PERCENT RAIN CHANCES THROUGH THE LATE EVENING AND OVERNIGHT AS THE FRONT COMES THROUGH. AN AREA OF HIGH PRESSURE LOOKS TO BUILD IN QUICKLY FOR WEDNESDAY AND SHOULD PUSH MOST THE RAIN TO THE EAST AND SOUTH OF THE FORECAST AREA. WENT AHEAD AND LOWERED THE RAIN CHANCES AND CONFINED THEM TO THE FAR SOUTHERN SECTIONS THINKING THE SUBSIDENCE IN THE WAKE OF THE SHORT WAVE TROUGH AND FROM THE SURFACE HIGH WILL SQUASH MOST OF THE RAIN. DIFFERENCES IN THE MODELS WITH THE TIMING AND STRENGTH OF THE NEXT SYSTEM. THE NAM AND GFS ARE ON THE STRONG SIDE OF THE MODEL SOLUTIONS AND SEEM TO BE OUTLIERS SO HAVE FAVORED THE 31.00Z ECMWF. THE SYSTEM NOW OVER BRITISH COLUMBIA WILL CONTINUE TO MOVE EAST SOUTHEAST AND BE DEEPENING AS IT APPROACHES THE AREA BECOMING THE STRONGEST ONCE IT IS PAST THE AREA. THIS SHOULD BRING BETWEEN 12 AND 20 PVU/S OF VORTICITY ADVECTION TO THE AREA FOR LATE WEDNESDAY NIGHT THROUGH THURSDAY. AS THIS SYSTEM APPROACHES...THE COLD FRONT WILL STALL TO THE SOUTH OF THE AREA WEDNESDAY AND THEN LIFT BACK TO THE NORTH AS A WARM FRONT WEDNESDAY NIGHT AS THE MAIN SURFACE LOW TRACKS FROM NORTH DAKOTA TOWARD THE U.P. OF MICHIGAN. AROUND 4 UBAR/S OF UP GLIDE ON THE 310K ISENTROPIC SURFACE SHOULD OCCUR WITH THE FRONTAL PASSAGE AND WHILE THE MOISTURE TRANSPORT DOES NOT TO BE OVERLY STRONG...IT SHOULD BE POSITIONED RIGHT INTO THE FRONT AS IT LIFTS THROUGH THE AREA. LOOKS AS IF LATE WEDNESDAY NIGHT WILL BE THE BEST COMBINATION OF FORCING FROM THE SHORT WAVE TROUGH AND LOW LEVEL THERMODYNAMICS AND RAISED THE RAIN CHANCES TO AROUND 60 IN ACCORDANCE WITH SURROUNDING OFFICES. THIS SYSTEM THEN LOOKS TO QUICKLY MOVE OFF TO THE EAST THURSDAY AND WOULD EXPECT TO SEE DIMINISHING RAIN CHANCES THROUGH THE DAY AS IT DOES. .LONG TERM...FRIDAY THROUGH TUESDAY MEDIUM RANGE MODELS SHOW A GOOD CONSENSUS TODAY WITH THE OVERALL UPPER AIR PATTERN. THE UPPER LEVEL TROUGH OVER EASTERN CANADA INTO THE EASTERN GREAT LAKES EARLY IN THE PERIOD WILL SHIFT EAST ALLOWING RIDGING OVER THE WESTERN CONUS TO BUILD OVER THE MIDWEST. THIS RIDGING IS THEN EXPECTED TO REMAIN IN PLACE UNTIL LATE IN THE PERIOD AS THE NEXT TROUGH SLIDES ACROSS SOUTHERN CANADA POSSIBLY IMPACTING THE UPPER MIDWEST EARLY NEXT WEEK. THE 31.06Z GFS IS THE FASTEST BRINGING THIS NEXT SYSTEM OUT WITH THE 31.00Z ECMWF IN BETWEEN THE GFS AND THE 31.00Z GFS ENSEMBLE MEAN. WITH THE STRENGTH OF THE UPPER LEVEL RIDGE AND MODEL BIASES OF BEING TOO QUICK TO BRING IN SOUTHWEST FLOW SYSTEMS...WOULD NOT BE SURPRISED TO SEE THIS SYSTEM BE SLOWED DOWN WITH LATER MODEL RUNS. HAVE MAINTAINED SOME SMALL RAIN CHANCES ACROSS THE NORTHEAST FRIDAY ON THE BACK SIDE OF THE DEPARTING GREAT LAKES SYSTEM. WITH THE GFS LOOKING TOO FAST WITH THE NEXT TROUGH...IT TRIES TO DEVELOP A WARM FRONT ACROSS THE AREA WITH THE CHANCE OF RAIN ALREADY BY LATE SUNDAY NIGHT. THE ECMWF AND GFS ENSEMBLES REMAIN DRY UNTIL LATE MONDAY AFTERNOON OR MONDAY NIGHT. HAVE TAKEN OUT THE RAIN CHANCES OVER MUCH OF THE HOLIDAY WEEKEND AND PUSHED THEM BACK TO AGREE BETTER WITH THE ECMWF AND GFS ENSEMBLES. && .AVIATION... SCT-OVC MVFR CLOUD DECKS EXPECTED TO PERSIST ACROSS THE AREA FOR THE REST OF THE AFTERNOON INTO THIS EVENING...IN THE MOIST LOW LEVEL AIRMASS AHEAD OF A COLD FRONT IN CENTRAL MN. ONE BAND OF SHRA/TSRA EXITING THE KLSE AREA EARLY THIS AFTERNOON BUT THE MN COLD FRONT EXPECTED TO IGNITE ANOTHER ROUND OF SHRA/TSRA ACROSS CENTRAL TO SOUTHWEST MN THRU THE AFTERNOON. THE FRONT/LINE OF SHRA/TSRA THEN EXPECTED TO SPREAD SOUTHEAST ACROSS THE TAF SITES MAINLY DURING THE EVENING HOURS...MOST LIKELY AT KRST IN THE 23-03Z TIMEFRAME AND KLSE BETWEEN 02-06Z...WITH IFR CIGS/VSBYS IN ANY TSRA/DOWNPOURS. A FEW OF THE TSRA COULD BE STRONG TO SEVERE LATE THIS AFTERNOON/EARLY THIS EVENING WITH STRONG GUSTY WINDS. WINDS SHIFT TO NORTHWEST AND NORTH BEHIND THE FRONT LATER TONIGHT...BUT LOWER LEVEL MOISTURE...MVFR CLOUDS/VSBYS IN BR AND SCT -SHRA BEHIND THE FRONT TO LINGER INTO THE MORNING HOURS OF WED. WEAK HIGH PRESSURE...SUBSIDENCE...LOW LEVEL DIVERGENT FLOW AND DIURNAL WARMING TO MIX/BREAK UP LOWER CLOUD DECKS WED MORNING WITH GENERALLY GOOD VFR CONDITIONS EXPECTED AT BOTH KRST/KLSE DURING THE LATE MORNING...AFTERNOON AND EVENING HOURS OF WED. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && SHORT/LONG TERM...04 AVIATION...RRS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 346 PM CDT TUE AUG 31 2010 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029- 032>034-041>044-053>055-061-011100- ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE- FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-LA CROSSE-MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU- VERNON-WABASHA-WINNESHIEK-WINONA- 346 PM CDT TUE AUG 31 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WEST CENTRAL AND NORTH CENTRAL WISCONSIN. .DAY ONE...LATE THIS AFTERNOON AND TONIGHT SHOWERS AND THUNDERSTORMS FROM EARLIER TODAY HAVE LIMITED THE INSTABILITY OVER PORTIONS OF THE AREA...MAINLY EAST AND SOUTH OF LA CROSSE. OVER SOUTHEAST MINNESOTA AND NEARBY AREAS...THE AIRMASS HAS BEEN ABLE TO WARM ENOUGH FOR IT TO BECOME MODERATELY UNSTABLE THIS AFTERNOON. THE MAIN FOCUS FOR SEVERE THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON AND THIS EVENING REMAINS A COLD FRONT PUSHING SOUTHEAST AND INTO THE MOIST...UNSTABLE AIRMASS OVER THE REGION. WITH THE MOST UNSTABLE AIRMASS OVER SOUTHEAST MINNESOTA AND NEARBY AREAS... AND THE FRONT ARRIVING THERE EARLIER THIS EVENING...A FEW OF THE THUNDERSTORMS MAINLY WEST AND NORTH OF LA CROSSE COULD BECOME SEVERE. THE MAIN SEVERE THREATS WOULD BE DAMAGING WINDS AND LOCALLY HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH LABOR DAY THERE IS A CHANCE FOR THUNDERSTORMS WEDNESDAY THROUGH THURSDAY ACROSS THE OUTLOOK AREA AS THE NEXT STORM SYSTEM MOVES INTO THE REGION. IT IS UNCERTAIN AT THIS TIME WHETHER ANY OF THESE STORMS MAY BECOME SEVERE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND THIS EVENING...MAINLY BETWEEN 5 PM AND 10 PM...AND MAINLY WEST OF A CHARLES CITY IOWA TO LA CROSSE AND BLACK RIVER FALLS LINE. .EMERGENCY MANAGEMENT COORDINATION... NO CALL IS SCHEDULED. HALBACH/RRS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 630 PM CDT TUE AUG 31 2010 IAZ008>011-018-019-029-MNZ079-086>088-094>096-WIZ032-033-041-053- 010100- ALLAMAKEE-BUFFALO-CHICKASAW-DODGE-FAYETTE-FILLMORE-FLOYD-HOUSTON- HOWARD-LA CROSSE-MITCHELL-MOWER-OLMSTED-TREMPEALEAU-VERNON-WABASHA- WINNESHIEK-WINONA- 630 PM CDT TUE AUG 31 2010 ...STRONG THUNDERSTORMS CONTINUE EARLY THIS EVENING... A LINE OF STRONG THUNDERSTORMS WILL CONTINUE TO TRACK EAST NORTHEAST EARLY THIS EVENING. THE LEADING EDGE OF THE STORMS WILL EXTEND FROM A BLAIR TO LA CROSSE WISCONSIN...TO DECORAH AND CALMAR IOWA LINE BY 8 PM. WIND GUSTS OF 30 TO 50 MPH WILL BE POSSIBLE...ALONG WITH HEAVY RAINFALL AND FREQUENT LIGHTNING. THE STORMS COULD DROP AS MUCH AS AN INCH OF RAIN IN A HALF HOUR. IF YOU ARE IN THE PATH OF THESE STORMS...TAKE COVER INSIDE A BUILDING AND STAY TUNED FOR UPDATES AND POSSIBLE WARNINGS. RIECK
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
635 PM CDT TUE AUG 31 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0630 PM TSTM WND GST 3 E SPRING VALLEY 43.69N 92.33W
08/31/2010 M47 MPH FILLMORE MN CO-OP OBSERVER
SUSTAINED 26 MPH FOR LAST 8 MINUTES. WSW WIND DIRECTION.
&&
DANBPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
714 PM CDT TUE AUG 31 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0705 PM TSTM WND GST 2 S BETHANY 44.00N 91.92W
08/31/2010 E30 MPH WINONA MN EMERGENCY MNGR
&&
DANBSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 725 PM CDT TUE AUG 31 2010 IAZ009>011-019-029-030-MNZ088-095-096-WIZ033-034-041-042-053-054- 010200- ALLAMAKEE-CHICKASAW-CLAYTON-CRAWFORD-FAYETTE-FILLMORE-HOUSTON-HOWARD- JACKSON-LA CROSSE-MONROE-TREMPEALEAU-VERNON-WINNESHIEK-WINONA- 725 PM CDT TUE AUG 31 2010 ...STRONG THUNDERSTORMS CONTINUE EARLY THIS EVENING... A LINE OF STRONG THUNDERSTORMS WILL CONTINUE TO TRACK EAST ACROSS THE REGION THIS EVENING. THE LEADING EDGE OF THE STORMS WILL EXTEND FROM A SHERWOOD TO TOMAH TO LIBERTY POLE WISCONSIN...TO WEST UNION IOWA LINE BY 9 PM. WIND GUSTS OF 30 TO 50 MPH WILL BE POSSIBLE...ALONG WITH HEAVY RAINFALL AND FREQUENT LIGHTNING. AS MUCH AS 1 INCH OF RAIN IN A HALF HOUR WILL BE POSSIBLE WITH THE STRONGEST STORMS. STAY TUNED FOR LATER UPDATES AND POSSIBLE WARNINGS. RIECK
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
728 PM CDT TUE AUG 31 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0721 PM TSTM WND GST WINONA 44.05N 91.66W
08/31/2010 M33 MPH WINONA MN AWOS
&&
DANBPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
739 PM CDT TUE AUG 31 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0725 PM TSTM WND DMG ARCADIA 44.25N 91.49W
08/31/2010 TREMPEALEAU WI LAW ENFORCEMENT
ONE TREE DOWN ON A CAR. NO OTHER DAMAGE IN THE AREA WAS
REPORTED.
&&
DANBThe La Crosse radar (KARX), 80 km away, was scanning. The volume nearest the first event began at 01:19 UTC.
1 flash flood, 1 thunderstorm wind. Local standard time, as filed.
A mudslide pushed water onto State Highway 37 southwest of the intersection with County Road N. A 24 hour total (ending at 6 a.m. CST) of 3.37 inches of rain was reported at Alma Lock and Dam 4.
A swath of wind damage was found across central Vernon County southwest through south of Viroqua along County Road NN and Getter Road. In this area, approximately 4 miles southwest of Viroqua, a barn was damaged and a roof was taken off a garage. Farther east along Getter Road, a barn was leveled, a small metal shed was destroyed and a field of sunflowers was damaged. The damage was initially believed to be caused by a tornado, but the storm survey did not find sufficient evidence to classify this as a tornado.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2010Every state in 2010This day in weather historyWarnings in Wisconsin, August 2010
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: 254950, 254951.