EF1 tornado in Winnebago County, Wisconsin

The tornado that formed near Poy Sippi crossed into Winnebago County at 8:04 pm CDT (1904 CST). The tornado moved along the north shore of Lake Poygan, causing most of its damage near Boom Bay on the northeast shore. Two homes were heavily damaged as portions of their roofs were partially ripped off (DI 2, DOD 4). Several other houses sustained lesser damage in this area. In addition, two small mobile homes were rolled on their side (DI 3, DOD 5) and many trees were uprooted or snapped. The tornado dissipated about 2 miles west of Winchester, although damage occurred east and southeast of this location from straight-line thunderstorm winds. The average path width was 100 yards.

Thunderstorms developed along and ahead of a cold front as it encountered moist and unstable air across Wisconsin.

A record number of tornadoes for April struck Wisconsin on April 10. Fifteen twisters affected the state as a strong spring storm moved across the western Great Lakes. In the National Weather Service Green Bay service area of northeast Wisconsin, ten tornadoes were reported, a record single-day outbreak for any month of the year.

In addition to the tornadoes, the lines of thunderstorms that developed produced plenty of straight line wind damage and large hail. Wind gusts, some estimated in the 80 mph to 100 mph range, downed numerous trees, damaged a small building, caused an injury and damage to two homes, toppled an 80-foot tall radio tower, threw a carport two houses away, and caused major damage to two industrial buildings. The largest hail reported was baseball size near Winneconne in Winnebago County.