The Severe Thunderstorm Winds of September 2, 2011 

Radar Imagery Images

Damage Reports

What Happened?

During the early morning hours, after a very warm and humid overnight, a complex of thunderstorms strengthened over northern Iowa. The somewhat "short" line of thunderstorms began to produce damaging winds near Mason City, Iowa around 540 am and those reports continued through La Crosse, Wisconsin (730 am) and into central Wisconsin (830 am). The thunderstorm complex produced a swath of wind damage all the way across Wisconsin into the Green Bay area.

Wind gusts with the line of storms were in the 40-55 mph range, but certain pockets within the line received winds up to 65-70 mph. Most of the wind damage was to trees with collateral damage to power lines, homes, and cars. No reports of injuries were received in the local area but many people were without power.

Storm Reports

Storm Reports After 7 am September 2, 2011
(G=Wind Gust in mph, W=Wind Damage)

Radar Imagery

Radar reflectivity loop Radar velocity loop
Click on image for a loop of the radar reflectivity from 6 to 9 am. Click on image for a loop of the radar-detected wind speeds with the storms. Yellow (red) indicates 45-55 mph (above 60 mph).

Images  

Damage Reports 

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE LA CROSSE WI
1213 PM CDT FRI SEP 02 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0558 AM     TSTM WND DMG     ST. ANSGAR              43.38N 92.92W
09/02/2011                   MITCHELL           IA   TRAINED SPOTTER

            8-10 INCH BRANCHES DOWN. ABOVE GROUND POOL FLIPPED OVER.

0558 AM     TSTM WND DMG     OSAGE                   43.28N 92.81W
09/02/2011                   MITCHELL           IA   LAW ENFORCEMENT

            TREE DOWN ON HOUSE.

0601 AM     HAIL             LYLE                    43.51N 92.94W
09/02/2011  E0.75 INCH       MOWER              MN   PUBLIC

0624 AM     TSTM WND DMG     CHESTER                 43.49N 92.36W
09/02/2011                   HOWARD             IA   EMERGENCY MNGR

            SEVERAL POWER LINES DOWN

0630 AM     TSTM WND GST     CHESTER                 43.49N 92.36W
09/02/2011  E70.00 MPH       HOWARD             IA   FIRE DEPT/RESCUE

            POWERLINES DOWN SOUTHSIDE OF CHESTER.

0635 AM     TSTM WND DMG     SPRING VALLEY           43.69N 92.39W
09/02/2011                   FILLMORE           MN   AMATEUR RADIO

            LARGE BRANCHES DOWN IN TOWN AND ONE TREE DOWN OVER COUNTY
            ROAD 1.

0635 AM     TSTM WND DMG     CRESCO                  43.37N 92.12W
09/02/2011                   HOWARD             IA   BROADCAST MEDIA

            SEMI TRUCK BLOWN OVER ON HIGHWAY 9. REPORTED VIA KCRG
            TELEVISION. TIME ESTIMATED.

0700 AM     TSTM WND GST     2 NE NEWBURG            43.59N 91.80W
09/02/2011  E60.00 MPH       FILLMORE           MN   TRAINED SPOTTER

            SEVERAL BRANCHES DOWN. OUTSIDE FURNITURE BLOWN AROUND.

0710 AM     TSTM WND GST     4 SW WINONA             44.01N 91.71W
09/02/2011  E60.00 MPH       WINONA             MN   TRAINED SPOTTER

0715 AM     TSTM WND DMG     8 NE CALEDONIA          43.72N 91.39W
09/02/2011                   HOUSTON            MN   LAW ENFORCEMENT

            TREES REPORTED DOWN ALONG STATE HIGHWAY 16.

0718 AM     TSTM WND DMG     TREMPEALEAU             44.01N 91.44W
09/02/2011                   TREMPEALEAU        WI   PUBLIC

            LARGE TREES DOWN ACROSS ROADWAYS AND ON POWER LINES

0719 AM     TSTM WND GST     PICKWICK                43.98N 91.60W
09/02/2011  E60.00 MPH       WINONA             MN   EMERGENCY MNGR

0721 AM     TSTM WND DMG     BROWNSVILLE             43.70N 91.28W
09/02/2011                   HOUSTON            MN   COUNTY OFFICIAL

            NUMEROUS TREES AND POWER LINES DOWN

0722 AM     TSTM WND DMG     CENTERVILLE             44.07N 91.45W
09/02/2011                   TREMPEALEAU        WI   NWS EMPLOYEE

            SEVERAL TREES DOWN ALONG HWY 35 BETWEEN CENTERVILLE AND
            TREMPEALEAU.

0722 AM     TSTM WND DMG     3 SW RENO               43.57N 91.32W
09/02/2011                   HOUSTON            MN   TRAINED SPOTTER

            18 INCH DIAMETER COTTONWOOD TREE DOWN. RECEIVED ABOUT
            0.70 INCHES OF RAIN IN 10 MINUTES.

0725 AM     TSTM WND DMG     3 ESE LA CROSSE         43.81N 91.18W
09/02/2011                   LA CROSSE          WI   NWS EMPLOYEE

            TREE DOWN ON APARTMENT BULDING ON 33RD STREET SOUTH JUST
            SOUTH OF STATE ROAD. ALSO TREES TOOK POWER LINES DOWN ONE
            BLOCK EAST ON DRIVE-IN ROAD.

0725 AM     TSTM WND DMG     3 SE LA CROSSE          43.80N 91.19W
09/02/2011                   LA CROSSE          WI   NWS EMPLOYEE

            TWO TREES DOWN ON BOMA ROAD AND HIGHWAY 33. SHELBY BALL
            FIELDS.

0726 AM     TSTM WND GST     4 N LA CROSSE           43.88N 91.23W
09/02/2011  M63.00 MPH       LA CROSSE          WI   ASOS

0726 AM     TSTM WND GST     ONALASKA                43.89N 91.22W
09/02/2011  M62.00 MPH       LA CROSSE          WI   PUBLIC

0727 AM     TSTM WND DMG     CHASEBURG               43.65N 91.10W
09/02/2011                   VERNON             WI   PUBLIC

            ROOF BLOWN OFF HOUSE IN CHASEBURG. REPORT RELAYED BY WXOW


0727 AM     TSTM WND GST     LA CROSSE               43.83N 91.23W
09/02/2011  M54.00 MPH       LA CROSSE          WI   AMATEUR RADIO

            MEASURED AT RADIO STATION DOWNTOWN.

0728 AM     TSTM WND DMG     LA CROSSE               43.83N 91.23W
09/02/2011                   LA CROSSE          WI   NWS EMPLOYEE

            TREES AND POWER LINES DOWN ON LOSEY BLVD/MAIN

0728 AM     TSTM WND GST     ONALASKA                43.89N 91.22W
09/02/2011  E65.00 MPH       LA CROSSE          WI   PUBLIC

0730 AM     TSTM WND GST     ONALASKA                43.89N 91.22W
09/02/2011  M62.00 MPH       LA CROSSE          WI   TRAINED SPOTTER

0730 AM     TSTM WND DMG     DECORAH                 43.31N 91.79W
09/02/2011                   WINNESHIEK         IA   LAW ENFORCEMENT

            NUMEROUS BRANCHES AND SMALL TREES DOWN IN AND NEAR
            DECORAH. SEVERAL LARGE TREES DOWN ACROSS HIGHWAY 139 NEAR
            KENDALLVILLE

0730 AM     TSTM WND GST     3 E LA CROSSE           43.83N 91.17W
09/02/2011  M52.00 MPH       LA CROSSE          WI   CO-OP OBSERVER

            MEASURED AT NWS LA CROSSE OFFICE

0731 AM     TSTM WND GST     GALESVILLE              44.08N 91.36W
09/02/2011  E60.00 MPH       TREMPEALEAU        WI   EMERGENCY MNGR

0733 AM     TSTM WND GST     WEST SALEM              43.90N 91.08W
09/02/2011  E60.00 MPH       LA CROSSE          WI   NWS EMPLOYEE

0734 AM     TSTM WND GST     3 NE WESTBY             43.68N 90.81W
09/02/2011  E70.00 MPH       VERNON             WI   TRAINED SPOTTER

            LARGE PINE TREE DOWN ON HOUSE. DAMAGE TO HOUSE.

0738 AM     TSTM WND GST     4 N LA CROSSE           43.88N 91.23W
09/02/2011  M63.00 MPH       LA CROSSE          WI   ASOS

            MEASURED AT LA CROSSE AIRPORT.

0740 AM     TSTM WND DMG     3 SE LA CROSSE          43.80N 91.19W
09/02/2011                   LA CROSSE          WI   NWS EMPLOYEE

            MULTIPLE TREES DOWN ON 16TH AND SOUTH AVE AND AREAS
            NORTHWARD. MOST ARE 1 TO 2 FOOT DIAMETER

0740 AM     TSTM WND DMG     STODDARD                43.66N 91.22W
09/02/2011                   VERNON             WI   LAW ENFORCEMENT

            NUMEROUS REPORTS OF TREES DOWN AND POWER OUTAGES. DAMAGE
            ALSO REPORTED BETWEEN STODDARD AND GENOA.

0747 AM     TSTM WND GST     SPARTA                  43.94N 90.81W
09/02/2011  E45.00 MPH       MONROE             WI   TRAINED SPOTTER

0747 AM     TSTM WND DMG     CASHTON                 43.74N 90.78W
09/02/2011                   MONROE             WI   PUBLIC

            TREE DOWN ON HOME. 3 TREES DOWN ON POWERLINE ON NEWPORT
            RD.

0750 AM     TSTM WND DMG     4 S NORWALK             43.78N 90.63W
09/02/2011                   MONROE             WI   PUBLIC

            14 INCH DIAMETER TREE DOWN. JACK PINE TREES SNAPPED OFF.
            LARGE OAK TREE SPLIT.

0750 AM     TSTM WND DMG     COON VALLEY             43.70N 91.01W
09/02/2011                   VERNON             WI   LAW ENFORCEMENT

            LOTS OF DOWNED TREES AND POWER LINES AND ALSO IN
            CHASEBURG AND STODDARD.

0752 AM     TSTM WND DMG     4 E CATARACT            44.09N 90.75W
09/02/2011                   MONROE             WI   TRAINED SPOTTER

            SEVERAL LARGE TREES DOWN ALONG COUNTY ROAD II

0752 AM     TSTM WND DMG     WILTON                  43.81N 90.53W
09/02/2011                   MONROE             WI   PUBLIC

            TREES DOWN ON POWER LINES. POWER OUT.

0756 AM     TSTM WND GST     4 E CATARACT            44.09N 90.75W
09/02/2011  E60.00 MPH       MONROE             WI   TRAINED SPOTTER

0756 AM     TSTM WND GST     FORT MC COY             44.02N 90.68W
09/02/2011  E45.00 MPH       MONROE             WI   TRAINED SPOTTER

            ALONG JACKSON PASS ON HIGHWAY 16

0759 AM     TSTM WND DMG     3 SW NORWALK            43.80N 90.67W
09/02/2011                   MONROE             WI   TRAINED SPOTTER

            TREE DOWN ON MOBILE HOME

0800 AM     TSTM WND DMG     OAKDALE                 43.96N 90.38W
09/02/2011                   MONROE             WI   PUBLIC

            VERY LARGE TREE BRANCHES DOWN. SOME FELL ON ROOF AND HIT
            SIDING CAUSING ROOF AND SIDING DAMAGE.

0802 AM     TSTM WND GST     TOMAH                   43.99N 90.50W
09/02/2011  E60.00 MPH       MONROE             WI   TRAINED SPOTTER

0810 AM     TSTM WND GST     VOLK FIELD              43.93N 90.27W
09/02/2011  M52.00 MPH       JUNEAU             WI   AWOS

0816 AM     TSTM WND DMG     3 SW NECEDAH            43.99N 90.11W
09/02/2011                   JUNEAU             WI   AMATEUR RADIO

            NUMEROUS TREES DOWN. SOME SNAPPED.

0820 AM     TSTM WND DMG     3 SE NECEDAH            43.99N 90.03W
09/02/2011                   JUNEAU             WI   AMATEUR RADIO

            NUMEROUS TREES DOWN

0820 AM     TSTM WND DMG     2 S NECEDAH             44.00N 90.07W
09/02/2011                   JUNEAU             WI   TRAINED SPOTTER

            JACK PINES SNAPPING FROM WIND GUSTS ESTIMATED AT 50 MPH.

0821 AM     TSTM WND DMG     10 N MAUSTON            43.95N 90.08W
09/02/2011                   JUNEAU             WI   TRAINED SPOTTER

            TREES DOWN NEAR SANDSTONE ESTATES. ONE FELL ON TRAILER IN
            TRAILER PARK.

0825 AM     TSTM WND DMG     ADAMS                   43.96N 89.82W
09/02/2011                   ADAMS              WI   LAW ENFORCEMENT

            TREES AND POWER LINES DOWN ACROSS ADAMS COUNTY. REPORTS
            OF ROADS BLOCKED...TREES DOWN ON HOMES AND CARS. NO
            INJURIES REPORTED. TIME ESTIMATED FROM RADAR BETWEEN 825
            AND 850AM

0825 AM     TSTM WND DMG     DELLWOOD                43.97N 89.96W
09/02/2011                   ADAMS              WI   AMATEUR RADIO

            SIX INCH TREES BLOWING DOWN FROM WINDS ESTIMATED AT 60
            MPH IN WESTERN ADAMS COUNTY NEAR CASTLE ROCK PARK.

0827 AM     TSTM WND DMG     2 N FRIENDSHIP          44.00N 89.82W
09/02/2011                   ADAMS              WI   AMATEUR RADIO

            POWER LINES DOWN.

0827 AM     TSTM WND DMG     2 N FRIENDSHIP          44.00N 89.82W
09/02/2011                   ADAMS              WI   AMATEUR RADIO

            TREES DOWN ABOUT A MILE SOUTH OF HIGHWAYS 13 AND 21
            INTERSECTION.

0849 AM     HEAVY RAIN       NECEDAH                 44.02N 90.07W
09/02/2011  M1.75 INCH       JUNEAU             WI   AMATEUR RADIO

0935 AM     HEAVY RAIN       5 SSE WILTON            43.75N 90.49W
09/02/2011  M1.10 INCH       MONROE             WI   PUBLIC

            RELAYED BY WXOW

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