Cleanup crews assembled Friday to salvage remnants of a northern Wisconsin resort demolished by one of at least five tornadoes that swept across the state.

Severe thunderstorms spawned tornadoes, produced baseball-size hail and dropped more than 6 inches of rain Thursday across the Upper Midwest, killing a swimmer in Illinois. In Wisconsin, at least two people went to the hospital with non-life threatening injuries.

Some of the worst damage was at the 25-acre Bear Paw Outdoor Adventure Resort near White Lake in Wisconsin. The northwoods resort runs along the Wolf River.

"Our restaurant's totally gone. There's maybe two walls standing," co-owner Shirlee Roshe said. "Our entire retail shop was blown across the road. Most of the merchandise was between the highway and the field on the other side of the highway."

At least one kayak was thrown more than 30 feet into the remnants of snapped pine trees.

"Most of our buildings are gone. I was just sickened," Roshe said as she headed to the property to direct volunteers' cleanup efforts.

She said one employee on the property when the storm hit suffered minor cuts to the head.

Hailstones 4 inches wide fell in Wisconsin Rapids, knocking out the windshields of several cars, including a police cruiser, dispatcher Karen Ryun said.

About 55,000 people in the state lost power, but service was restored to all but about 7,500 by Friday morning, utility companies said.

In Illinois, 19-year-old Joshua Simpson drowned Thursday while trying to save a female friend who was having trouble swimming in the choppy waters of Lake Michigan near Waukegan, authorities said.

About 7,000 ComEd customers in northern Illinois were without power Friday morning, spokesman Jeff Burdick said. He said more outages were expected as moderate winds could knock already-weakened branches onto power lines.

Heavy winds whipped across Chicago, snarling air travel. About 400 flights at O'Hare International Airport were canceled Thursday evening, according to Wendy Abrams, spokeswoman for the Chicago Department of Aviation.

Claudia Boelter of Elizabeth, Minn., took cover in a neighbor's house after seeing a tornado touch down on a nearby lake.

"My husband was pulling some lawn furniture off of our deck, when all of a sudden a black cloud came out right in front of us," she said. "We ran next door, and I looked out their living room window. I could see this cloud that was down on the lake, rotating and pulling water up."

Hail the size of golf balls was reported in parts of Minnesota. Gusty winds knocked out power in parts of the Twin Cities.

In North Dakota, where the storms began late Wednesday, heavy rain washed out roads. Bowman County emergency manager Dean Pearson said he had reports of 1 1/2 to 6 1/4 inches of rain overnight.

"We've got some roads that are washed out and some areas that are still running over the roadway," Pearson said. "It's been slow getting started (to assess the damage) because it's so muddy that it's hard to get around."