EF1 tornado in Waukesha County, Wisconsin

This EF1 tornado affected the Big Bend and Muskego area, and spun up a little more than 2 miles north of Big Bend about 1/10 of a mile southeast of the intersection of Interstate 43 and STH 164. The tornado moved east, dissipating about 1/2 mile south of Tess Corners, just northwest of the intersection of Woods Road and Durham Drive. The roof of the Tess Corners Fire Department tore off, and the U.S. Post Office building in Muskego was damaged when an air conditioning unit was blown off the roof. Several post office vehicles were also damaged. The building housing Muskego Beer and Liquor was badly damaged when a wall collapsed and destroyed half the building. All together, 35 residential dwellings were minimally affected, and 41 homes sustained minor damage. Seventeen businesses were minimally affected, and 1 sustained major damage. Some crops were damaged, but no information on loss estimates was available. Total estimated private sector damage was about $430,000. Public sector structural damage totaled about $15,000. Additionally, other public service (non-damage) costs totaled $65,000; which included $45,000 for debris clearance, $10,000 for protective measures, and $10,000 for road systems. Hundreds of trees were uprooted or damaged. Starting location point was Lat 42.91015 Lon -88.21483 with the ending point Lat 42.91118 Lon -88.09850. The EF-rating was based on DI 27 (TH) DOD3 which suggests a wind speed of 105 mph. The average path width was 90 yards.

Strong to severe thunderstorms developed across much of south central and southeast Wisconsin during the evening of June 21, 2010. A vigorous upper level disturbance helped to support deep vertical motions in the atmosphere, along with strong deep layer wind shear. This lift acted on a warm and very moist atmosphere, carried into the region on a 40 to 50 knot low-level jet. The result was powerful rotating thunderstorms, with damaging straight line winds, large hail, and in this case, 5 tornadoes. At one point during the height of the event, around 48,000 customers in southeast Wisconsin were without electric power due to downed power lines. However, power-line and power-pole loss estimates were not available and do not show up as damage amounts in any individual event within this severe weather episode.