As a cold front moved across Wisconsin, it sparked severe thunderstorms during the late evening of August 15th into the early morning hours of August 16th. These storms produced a path of damaging winds and large hail from the southern portions of Buffalo County to the southeast corner of Adams 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.
As a cold front moved across Wisconsin, it sparked severe thunderstorms during the late evening of August 15th into the early morning hours of August 16th. These storms produced a path of damaging winds and large hail from the southern portions of Buffalo County to the southeast corner of Adams County. The most concentrated wind damage was near the Trempealeau-La Crosse County line, including communities of Galesville and Holmen, where estimated winds of 60 mph knocked down several trees and power lines. Most of the hail was estimated to be about the size of a quarter with this falling for up to 10 minutes at Perrot State Park (Trempealeau 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 15, 10:49 PM CST, 11 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1149 PM CDT WED AUG 15 2012 .SHORT TERM...OVERNIGHT 1149 PM CDT WED AUG 15 2012 THE FOCUS OVERNIGHT CONTINUES TO BE WITH THE THUNDERSTORMS WITH WHEN THEY WILL OCCUR AND HOW STRONG THEY COULD BECOME. THE EARLIER SUPERCELL IN WEST CENTRAL MINNESOTA DID NOT MATERIALIZE INTO A SQUALL LINE AND WITH THAT IT GREATLY REDUCED ANY CHANCES FOR SEVERE WEATHER ACROSS THE REGION. HOWEVER...ADDITIONAL CONVECTION HAS FORMED OUT AHEAD OF THE COLD FRONT ALONG THE EASTERN RIM OF THE CONTINUALLY WEAKENING INSTABILITY AXIS. THE 16.01Z RAP/HRRR CONTINUE TO SHOW ADDITIONAL DEVELOPMENT FURTHER SOUTHWEST ALONG THE FRONT OVERNIGHT AS LOW LEVEL MOISTURE TRANSPORT INCREASES THROUGH THE NIGHT. HOWEVER...WITH 0-3KM MUCAPE AROUND 1000 J/KG OVERNIGHT...AM NOT EXPECTING WIDESPREAD SEVERE WEATHER THOUGH A FEW STORMS COULD PRODUCE SOME STRONG WINDS AND HAIL. QUITE A BIT OF POSITIVE LIGHTNING STRIKES SHOWING UP WITH THE STORMS MOVING INTO WABASHA COUNTY AS WELL FOR WHAT ITS WORTH. GIVEN THE INCREASING MOISTURE TRANSPORT AND UPPER LEVEL SUPPORT WITH THE TROUGH MOVING IN...DID NOT BACK OFF ON PRECIPITATION CHANCES AFTER 6Z MUCH DESPITE CONFIDENCE NOT BEING TOO HIGH GIVEN THIS EVENING/S MESO MODELS OVER-ABUNDANCE OF CONVECTION TO THE SOUTH. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 352 PM CDT WED AUG 15 2012 FROM SATURDAY NIGHT THROUGH THROUGH MONDAY NIGHT...THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THE UPPER LEVEL WILL REMAIN CENTERED OVER JAMES BAY. MEANWHILE A RIDGE REMAINS ANCHORED OVER THE ROCKIES. THIS WILL KEEP A NORTHWEST FLOW LOCATED ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. AS A RESULT...TEMPERATURES WILL AVERAGE BELOW NORMAL. THIS IS FAIRLY TYPICAL IN AUGUST WHEN YOU HAVE A DEVELOPING EL NINO. SINCE 1950...THERE HAVE BEEN 13 EL NINOS WHICH HAVE AFFECTED AUGUST. 10 OUT OF THESE 13 /77 PERCENT/ EL NINOS SAW AUGUST TEMPERATURES AVERAGE BELOW NORMAL. IN THE CASE OF THE MAXIMUM TEMPERATURES...12 OUT 13 EL NINOS /92.3 DEGREES/ HAD BELOW NORMAL TEMPERATURES. BEYOND THIS TIME PERIOD...THE MODELS STRUGGLE WITH A WAVE MOVING INTO THE PACIFIC NORTHWEST. MANY OF THE MODELS SHOW THAT THIS WAVE WILL FLATTEN THE RIDGE OVER THE ROCKIES AND PLACE THE AREA MORE IN A ZONAL FLOW. THE GFS GENERATES SOME PRECIPITATION ACROSS THE REGION FROM TUESDAY NIGHT AND WEDNESDAY. MEANWHILE THE ECMWF KEEPS THE AREA DRY. DUE TO THESE DIFFERENCES...LOWERED THE CONSALL PRECIPITATION TO FROM AROUND 50 PERCENT TO AROUND 20 PERCENT. && .AVIATION...THROUGH 06Z FRIDAY 1149 PM CDT WED AUG 15 2012 THE MAIN SHORT TERM ISSUES AT THE TAF SITES ARE WITH THE THUNDER CHANCES OVERNIGHT INTO THURSDAY MORNING ALONG WITH ANY POTENTIAL MVFR CEILINGS THAT MAY DEVELOP. AT 11 PM...A CLUSTER OF STORMS WERE MOVING JUST TO THE NORTH OF RST/LSE AND ARE EXPECTED TO MAINLY STAY TO THE NORTH OF THEM. A BRIEF SHOWER/THUNDERSTORM CAN NOT BE RULED OUT EARLY THIS MORNING...BUT THEY SHOULD CLEAR RATHER QUICKLY AS THE COLD FRONT MOVES IN FROM THE WEST. WINDS WILL SHIFT TO THE NORTHWEST AND SHOULD REMAIN GUSTY THROUGH MUCH OF THURSDAY BEFORE A RIDGE OF HIGH PRESSURE MOVES IN TONIGHT. MVFR CEILINGS THEN APPEAR SET TO DROP DOWN INTO THE REGION QUICKLY BEHIND THE FRONT WITH 1KFT-2KFT CEILINGS STARTING TO DROP SOUTH ACROSS MINNESOTA. THESE LOW CIGS SHOULD CLIMB DURING THE DAY AS SURFACE TEMPERATURES WARM AND PROMOTES SOME DEEPER MIXING. && .ARX WATCHES/WARNINGS/ADVISORIES... 352 PM CDT WED AUG 15 2012 WI...NONE. MN...NONE. IA...NONE. && SHORT TERM...HALBACH LONG TERM...BOYNE AVIATION...HALBACH
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 954 PM CDT WED AUG 15 2012 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-161200- 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- 954 PM CDT WED AUG 15 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MINNESOTA... NORTHEAST IOWA...AND WESTERN INTO CENTRAL WISCONSIN. .DAY ONE...OVERNIGHT THUNDERSTORMS ARE EXPECTED TO BECOME MORE NUMEROUS OVERNIGHT THROUGHOUT THE REGION. SEVERE WEATHER DOES NOT LOOK LIKELY... THOUGH A FEW STORMS COULD PRODUCE GUSTY WINDS TO 40 MPH...SMALL HAIL...BRIEF HEAVY DOWNPOURS AND FREQUENT LIGHTNING. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SOME THUNDERSTORMS MAY LINGER INTO THURSDAY MORNING...BUT ARE NOT EXPECTED TO BE SEVERE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT. .EMERGENCY MANAGEMENT COORDINATION... NO WEBINAR IS SCHEDULED. RABERDING/DTJ/HALBACH
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 1134 PM CDT WED AUG 15 2012 MNZ079-088-WIZ032>034-160530- BUFFALO-JACKSON-TREMPEALEAU-WABASHA-WINONA- 1134 PM CDT WED AUG 15 2012 AT 1130 PM...DOPPLER RADAR INDICATED STRONG THUNDERSTORMS FROM NELSON TO RATTLESNAKE RIDGE...MOVING EAST AT 40 MPH. WIND GUSTS OF 40 TO 50 MPH...SMALL HAIL AND TORRENTIAL DOWNPOURS MAY ACCOMPANY THESE STRONG THUNDERSTORMS. THE STRONG THUNDERSTORMS WILL BE NEAR... MODENA...BUFFALO AROUND 1140 PM... ARCADIA...INDEPENDENCE AROUND 1210 AM... WHITEHALL AROUND 1220 AM... BLAIR AROUND 1230 AM... LIGHTNING CAN BE A KILLER AND MAY STRIKE MILES AWAY FROM THE STORM. MOVE INDOORS OR FIND A VEHICLE TO SHELTER IN. SMALL HAIL MAY FALL FOR SEVERAL MINUTES AND COVER THE GROUND. THIS COULD LEAD TO DIFFICULT DRIVING CONDITIONS AND THE FORMATION OF FOG. THESE WIND GUSTS COULD BLOW AROUND OUTDOOR FURNITURE AND OTHER LIGHT OBJECTS. SMALL BRANCHES MAY ALSO FALL. SEEK SAFE SHELTER INSIDE A BUILDING. HALBACH
The La Crosse radar (KARX), 54 km away, was scanning. The volume nearest the first event began at 05:00 UTC.
14 thunderstorm wind, 4 hail. Local standard time, as filed.
Trees were blown down near Fountain City.
A large tree was blown down onto County Road M near the intersection of County Road YY just east of Fountain City.
Strong winds blew down corn and combined with nickel sized hail stripped crops along and near Highway 35 between Galesville and Centerville.
Quarter sized hail fell for around 10 minutes at Perrot State Park.
Power lines and tree branches were blown down near the Holmen Police Department.
Trees were blown down across County Road V and Moe Coulee Road north of Holmen.
A large tree was blown down on a house east of Holmen. Large branches on the tree pierced through the roof allowing water to enter the house.
An estimated 60 mph wind gust occurred on the south side of Holmen.
Trees and power lines were blown down near the intersection of State Highways 162 and 16 north of Bangor.
A 60 mph wind gust along with one inch hail occurred in Leon.
Dime to quarter sized hail fell and was accompanied by wind gusts of 45 to 50 mph just south of Sparta along Interstate 90 at Exit 25 for State Highway 27.
Trees were blown down on County Road A between Hustler and New Lisbon.
Trees were blown down across U.S. Highway 12/State Highway 16 between Mauston and New Lisbon.
Trees were blown down northeast of Plainville.
Trees were blown down south of Friendship.
Trees were blown down south of Brooks.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2012Every state in 2012This day in weather historyWarnings in Wisconsin, August 2012
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: 405014, 405015, 409585, 405017, 405021, 405018, 405019, 405020, 405022, 405023, 405024, 405644, 405645, 406152, 406153, 406385, 406386, 406387.