EF1 tornado in Lafayette County, Wisconsin

An EF1 tornado developed in a rural area about 4.5 miles southeast of Darlington about 1/2 mile southwest of the intersection of Walnut Road and Pecatonica Road. The tornado moved east-northeast for about 2.2 miles, and dissipated about 0.4 miles north of the intersection of Walnut Road and Tish Road. Tornadic damage was sporadic in the second-half of the tornado's life. One residence experienced siding and window damage. An outbuilding used as a garage on a farmstead lost its metal roof. One large hardwood tree was blown down and other tree limbs were broken. Minor crop damage was noted, but loss estimates were not available. The exact start location was Lat 42.63352 Lon. -90.04077. The exact end location was Lat. 42.64554 Lon. -90.00035. The EF-rating was based on DI 1 (SBO), DOD 5 which suggests wind speeds between 90 and 95 mph. Average path width was 50 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.