EF1 tornado in Shawano County, Wisconsin

The long-track tornado first touched down about two miles east of Mattoon at 4:31 PM CDT and slowly intensified as it quickly exited the county about three miles east-northeast of Mattoon and moved into Menominee Co. Several trees were knocked down and uprooted (DI 28, DOD 4). This segment of the tornado was rated EF1 with an average path width of 250 yards.

An unseasonably strong upper level storm system and deep surface low pressure (with central pressure as low as 979 mb) interacted with a cold front that moved from west to east across the area during the late afternoon and evening. A moist and unstable airmass ahead of the cold front provided the fuel to generate severe thunderstorms that included five tornadoes, near record-size hail and damaging winds. Thousands of homes sustained damage and about 15,000 customers lost power during the storms, some for almost 3 days as trees blocked roads and slowed repair work to power lines. Four people sustained minor injuries, and total damage from the storms exceeded $60 million.

The first tornado of the outbreak moved across eastern Marathon County shortly after 4:00 PM CDT, producing damage to several homes. The tornado was rated EF2.

A second thunderstorm produced a weak tornado in Wood County, which was rated EF0. The same storm responsible for this tornado produced softball size hail that damaged thousands of homes, several businesses and hundreds of vehicles. One hailstone that fell in Port Edwards measured 5.50 inches in diameter, making it the second largest hailstone on record in Wisconsin.

The same supercell thunderstorm that produced the Marathon County tornado also produced a long-track tornado across northeast Shawano, northwest Menominee, southeast Langlade and northern Oconto counties. This tornado was on the ground for 47 minutes, covering 40.1 miles, and destroyed 14,400 acres of woodlands (timber loss was estimated at $12.5 million) and dozens of buildings along its path. The twister, which was over one-half mile at times, was rated EF3, with peak winds estimated of 150 to 160 mph. The storm responsible for the tornado also produced significant straight-line wind damage as it moved into western Marinette County.

The fourth tornado of the outbreak, rated EF1, developed near Cedarville in Marinette Co., which was from the same thunderstorm that produced the long-track tornado.

The final tornado of the afternoon and evening touched down near Harmony in Marinette Co. This tornado was rated EF1.

Details of the tornadoes, hail, and wind damage can be found in the event narratives of the affected counties.