EF1 tornado in Calumet County, Wisconsin

The tornado that formed in Outagamie County 3.5 miles east of Greenville at 12:38 am CDT, and briefly moved across Brown County, entered Calumet County 1.6 miles north of Forest Junction at 12:50 am CDT. The tornado damaged about three dozen trees (DI 28, DOD 3 and 4). Two metal truss towers collapsed under the weight of several high voltage power lines (that weighed two pounds per foot) which were likely moving in unison as their resonance frequency was reached. Engineers that inspected the damage estimated winds of 100 mph. Nearby trees sustained relatively minor damage (DI 28, DOD 2 and 3). The average path width in Calumet County was 125 yards.

A line of severe thunderstorms, known as a quasi-linear convective system (QLCS), produced six tornadoes and widespread damaging winds across east-central Wisconsin during the late night hours of August 6-7. The storms formed ahead of a cold front that also produced severe weather in Minnesota and western Wisconsin.

The tornadoes occurred within about 50 minutes--between 12:22 am and 1:10 am CDT. Hundreds of homes, businesses and farm buildings were damaged. Two injuries occurred at a campground in Waupaca County. Thousands of trees and power lines were also downed, leaving tens of thousands of people without power. The strongest tornado of the event reached EF2 intensity (winds estimated at 115 to 120 mph). This tornado caused significant damage to a church in New London.

The six tornadoes that occurred on August 7 were the most nighttime tornadoes in a single event in northeast Wisconsin since accurate tornado records began (1950).