Quinn Boehning, 29, was killed after crashing into a fallen tree and power line near the town of Ripon about 6 a.m. Thursday, according to the State Patrol.
The severe weather began Wednesday evening in northwestern Wisconsin and pushed south and east with the last tornado warning expiring around 2 a.m. Thursday.
At least four tornadoes touched down in Jefferson and Waukesha counties early Thursday, the weather service said.
The first touchdown was outside Watertown just after 1 a.m. with wind speeds close to 85 mph. The second touched down at 1:15 a.m. just outside the town of Concord in Jefferson County, where wind speeds were estimated at nearly 100 mph. The tornado caused significant damage to trees, roofs and barns.
The third confirmed tornado was just south of Sunset Park in Waukesha at about 1:30 a.m. with wind speeds close to 85 mph. The fourth occurred south of Dousman, with peak wind speeds of 100 mph, according to the NWS.
Utility crews worked Thursday to restore service to about 90,000 customers statewide who lost electricity during the storms. By Friday morning, about 6,300 customers remained without service, according to the tracking website poweroutage.us.