Winds of up to 170 mph fueled the tornado that swept through Wadena and damaged more than 200 homes last week, yet it was the weakest of three storms that hit the area, the National Weather Service determined Sunday.
All three tornados are considered EF4s on the Enhanced Fujita scale, which means they had estimated peak wind speeds of between 166 mph and 200 mph based on the damage they caused.
But the Wadena tornado was the most damaging, leaving a trail of destruction a mile wide and 10 miles long. It caused ripped through a residential area and hurled several school buses hundreds of feet through the air.
"All I know is that it was horrific," Wadena Mayor Wayne Wolden, who rode out the storm in his basement with his teenage daughter, told the Brainerd Dispatch.
Displaced residents in southwest Wadena were allowed back to their homes Sunday to make repairs or get personal items.
The series of storms that hit the state Thursday killed three people, injured dozens more and damaged hundreds of homes. Gov. Tim Pawlenty declared a state of emergency in Faribault, Freeborn, Olmsted, Otter Tail, Polk, Steele and Wadena counties.
The tornado that hit the Almora-Bluffton area had winds up to 175 mph and did damage along a path measuring 1.3 miles wide and 36 miles long. It obliterated several homes and businesses.
The twister that hit Holmes, N.D., had peak winds estimated at 185 mph and moved primarily through rural areas, severely damaging a few structures.
But the most serious damage was in Wadena, where officials reported 232 homes were hit, and in a rural area just west of Albert Lea in southern Minnesota, where about 60 rural properties saw damage.
The Wadena tornado made its initial touchdown about three miles southwest of town around 5 p.m. Thursday, then moved northeast before lifting up 20 minutes later about seven miles north of town, according to a National Weather Service report released Sunday.
The weather service called it a "multi-vortex" storm with several funnel clouds pivoting around a common center. Based on the damage it caused, the weakest of the funnel clouds packed winds of more than 86 mph.
Residents allowed back into their homes Sunday were warned to be careful of branches and other debris and watch out for unstable structures and trucks hauling materials around the area.
"It's going like gangbusters," Wolden said of recovery efforts. "The sun is shining, we're working hard and it's been a happy Father's Day. Again, people are just so thankful for their lives."
Security has been tightened in the area and people who don't live in the area have been asked to stay away, said city spokeswoman Judy Jacobs. Gawkers have slowed clean-up efforts and "there have been some cases of looting," she said.
The weather service is still investigating other tornado reports in the area. Weather service teams were assessing the damage caused by the tornados in southern Minnesota on Sunday, but their report was not finished Sunday evening.
(Copyright 2010 by The Associated Press. All Rights Reserved.)