The National Weather Service says the storm damage at Lake Panorama is consistent with an EF2 tornado.
The preliminary results show the twister took a path from southeast of Guthrie Center to northeast of Yale and was on the ground for 16.7 miles.
The most serious damage was found around Lake Panorama where several houses had the roofs ripped off. Downed trees and docks blown from the shore were also found.
There was significant damage to trees at the Lake Panorama Golf Course.
Officials say no injuries were reported of Lake Panorama residents.