National Weather Service United States Department of Commerce

Strong thunderstorms moved across southern Wisconsin during the evening of Sunday, June 29th, 2014.  Significant tree and structure damage was reported in portions of Iowa and Dane counties.  A National Weather Service storm survey was conducted of the most severe damage on Monday. 

The NWS storm survey determined that three tornadoes occurred in Iowa and Dane counties, between 10 pm and midnight.  The preliminary specifics are listed below:


 

PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 243 PM CDT TUE JUL 01 2014

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

1030 PM     TORNADO          6 NNW DODGEVILLE        43.04N 90.18W
06/29/2014  F2               IOWA               WI   NWS STORM SURVEY
            TORNADO RATED EF2 TOUCHED DOWN 6 MILES NNW OF DODGEVILLE
            AT 1030 PM. THREE LARGE AGRICULTURAL OUTBUILDINGS WERE
            DESTROYED. SIGNIFICANT ROOF DAMAGE TO TWO HOMES. NUMEROUS
            TREES SNAPPED IN HALF. CONCRETE SILO DESTROYED. TORNADO
            LIFTED AT 1040 PM 7.9 MILES NE OF DODGEVILLE. ESTIMATED
            PATH LENGTH OF 4.9 MILES. MAXIMUM PATH WIDTH OF 400
            YARDS.

1030 PM     TORNADO          3 N DODGEVILLE          43.01N 90.13W
06/29/2014  F2               IOWA               WI   NWS STORM SURVEY
            TORNADO RATED EF2 TOUCHED DOWN 3 MILES NORTH OF
            DODGEVILLE AT 1030 PM CDT. LARGE CAMPER-TRAILER DESTROYED
            AND TOSSED 100 YARDS. METAL BUILDING SIGNIFICANTLY
            DAMAGED. TORNADO HAD PATH LENGTH OF LESS THAN ONE QUARTER
            MILE AND LIFTED ABOUT 1031 PM CDT. MAXIUMUM PATH WIDTH OF
            150 YARDS.

1127 PM     TORNADO          2 N OREGON              42.96N 89.38W
06/29/2014  F1               DANE               WI   NWS STORM SURVEY

            TORNADO RATED EF1 TOUCHED DOWN 2 MILES NORTH OF OREGON AT
            1127 PM CDT. TORNADO CAUSED EXTENSIVE TREE DAMAGE.
            NUMEROUS LARGE PINE TREES SNAPPED. TORNADO LIFTED 3.9
            MILES NORTHEAST OF OREGON AT 1130 PM. ESTIMATED PATH
            LENGTH OF 2.3 MILES AND MAXIMUM PATH WIDTH OF 200 YARDS.

 

The below image illustrates the path lengths and locations of all three tornadoes (click for larger view):

All tornado paths

 

Close up of Individual Tornado Paths - Click for larger view

Here is a radar animation between 10 pm and 11 pm CDT Sunday evening.  The upper left panel shows radar reflectivity, the upper right panel shows storm relative velocity, the lower left panel display velocity, and the lower right panel shows correlation coefficient, which can display storm debris lofted by a tornado. (Click the below image for a larger view) 

Sunday evening radar animation

A very strong circulation produced an EF1 tornado which touched down just east of Fennimore in Grant County around 10 pm.  The tornado then lifted about 10 minutes later, but the strong circulation continued into Iowa County as indicated in the Storm Relative Velocity image.  The circulation is indicated by the green (inbound) pixels next to the red (outbound) pixels in the upper right image. 

The tornado caused EF2 damage along County Road ZZ, just north of Governor Dodge State Park, about 6 miles north of Dodgeville, around 1030-1040 pm CDT. Around that time, a weak 
Tornado Debris Signature (TDS) showed up in the Correlation Coefficient parameter, indicated by the blue and green pixels just north of highway 18. This was indicative of debris from the tornado being lofted, which was picked up by the radar.  This is how Doppler radar can now confirm a tornado is occurring.  However since the TDS was farther south than the main circulation, and our storm survey crew picked up more tornado damage farther south toward highway 18, a second tornado may have occurred. 

The tornado warning for Iowa County was issued at 10:09 pm CDT, before it entered Iowa County, which was in effect until 11:00 pm CDT.  A second Tornado Warning was issued for the same storm that extended it until 11:15 pm CDT for eastern Iowa and western Dane Counties. 

 


 

 

Photos of Damage in Dane County:

 

   
   

 

 


 

 Photos of Damage in Iowa County:

 

Highland Area Hyde Store
6 Miles North of Dodgeville  

 


Hentz/Wood/Cronce/MBK
NWS Milwaukee/Sullivan, WI