A storm that appeared to spawn at least on tornado slammed parts of western Michigan on Saturday, causing extensive damage but no injuries or loss of life, authorities said.

State Police spokesman Dale Hinz said damage from the storm stretched up to 20 miles from just south of Bangor to the small community of Grand Junction, about 60 miles southwest of Grand Rapids.

A number of homes had their roofs ripped off, trees were uprooted and vehicles damaged. He said a business called True Blue Farms in Grand Junction sustained extensive damage. But there were no reports of injuries or fatalities, Hinz said.

National Weather Service meteorologist Jared Maples said survey teams were sent out Saturday evening to assess the damage and determine if a tornado actually touched down.

"Radar signature is pretty evident that something has struck," said Maples, who is in the weather service's Grand Rapids office.

Parts of Van Buren, Allegan and Kent counties, and the outskirts of Grand Rapids saw some of the worst weather.

Tornado and thunderstorm warnings were issued.

"I didn't know what I was going to see when I looked up," said Andy Bloos, who took shelter in the basement of his Grand Rapids-area home. "I could feel my house shaking and my roof buckling. You could hear things banging on the roof of the house."

He emerged after the storm passed to find a hole in his roof.

More than 20,000 utility customers in several counties lost power, according to Consumers Energy.