Several tornadoes swirled through western Wisconsin communities Sunday, leaving behind snapped trees, blown-off roofs and damaged buildings but no reports of serious injuries.

Elsewhere in the state, severe thunderstorms accompanied by hail of varying sizes and winds close to hurricane force damaged businesses and homes and knocked out power for thousands.

A tornado touched down on the south side of La Crosse late Sunday afternoon, prompting authorities to order the evacuation of residents in a neighborhood because of fears of a gas leak.

An estimated 200 homes and businesses were damaged, leading the mayor of La Crosse to declare a state of emergency.

The tornado path was approximately three to four city blocks wide and about a mile in length, according to La Crosse County Emergency Management officials. Two people reported minor injuries. Shelters were set up at two schools.

In Sparta, a tornado flipped several cars and destroyed numerous windows at a Chevrolet dealership; it also snapped trees and damaged billboards. Preliminary estimates show the Sparta tornado was about 70 yards wide and a weak EF-1 tornado, the National Weather Service reported.

Three people were injured in Wood County, including one at a campground near the Town of Saratoga when the storm hit.

Twisters also touched down in the Juneau County community of Mather, where numerous trees blocked state Highway 173, and in Taylor County about eight miles north of Gilman. A funnel cloud was seen in Clark County, about one mile north of Curtiss.

Hail ranged in size from pea to marble to golf ball, depending on the area. And in Marquette County, near Westfield, trained spotters reported baseball- and softball-sized hail, said Rusty Kapela, National Weather Service meteorologist in Sullivan. At the National Weather Service office in Sullivan, 1.25-inch hail fell on the metal roof.

"All of a sudden you could hear 'boom, boom, boom,'" said Kapela.

In southeastern Wisconsin, strong winds blew down branches and trees and damaged roofs. Part of the roof of the Days Inn at S. 13th St. and W. College Ave. in Oak Creek was torn off, and a roof on a home near Paddock Lake was blown off by high winds recorded at 60 to 65 mph.

Based on damage reports in south central and southeastern Wisconsin, winds probably reached the low end of hurricane force - which is considered 74 mph or more, said Kapela, who estimated that winds likely were in the 75 to 80 mph range in parts of Walworth, Kenosha and Green Lake counties.

At the height of the storms, about 11,000 We Energies customers lost power, said company spokeswoman Cathy Schulze. By 10:30 p.m., power was still out for 7,400 customers, and repair crews were working throughout the night Sunday to restore electricity.

At Gundersen Lutheran Health System in La Crosse, the tornado did not damage the hospital and no patients or staff members were injured, said spokesman Chris Stauffer.

As of 9 p.m. Sunday no one had sought treatment for storm-related injuries.

"Ironically we were at a shift change, so we had extra personnel on hand and asked them to stay awhile," Stauffer said.

The tornadoes and thunderstorms were caused by a low-pressure system that moved up from eastern South Dakota toward Duluth, Minn., at the same time a strong jet stream curved from Kansas and Nebraska across Iowa and into western Wisconsin, said Kapela. Warm, moist air was pulled up into the state, which, combined with a wind shear from the jet stream and warm temperatures baking the ground, spawned twisters and thunderstorms.

Because of the unstable weather conditions, the National Weather Service issued a tornado watch for about eight hours Sunday afternoon and evening for 36 Wisconsin counties, including Milwaukee, Ozaukee, Racine, Washington and Waukesha.