Tornadoes and thunderstorms have killed at least seven people in the US state of Ohio, officials say.
At least 50 houses were destroyed and many more damaged in north-western Ohio, local firefighter chief Todd Walters told AP news agency.
Several people were taken to hospitals as the storm left an eight-mile (13km) path of destruction, hitting Lake Township particularly hard.
The extreme weather also affected parts of Illinois and Michigan.
The high school in Lake Township was among the hardest-hit buildings.
Some buses were thrown across the school car park, Superintendent Jim Witt said.
Lake Township Police Chief Mark Hummer described the affected area as "like a war zone".
He said a child was among the victims.
Mr Hummer said later that the authorities had finished searching damaged buildings and he was not aware of anyone being reported missing, but fields and woods were still being searched.
In Michigan, the Fermi nuclear power plant on the shore of Lake Erie was shut down after high winds tore a side from one of the buildings.
Dan Smith, public information officer for Monroe County, said investigators were inspecting the plant and it was expected to go back into operation soon.
An eyewitness in Illinois said the city of Streator had been badly damaged.
"I saw people coming out of their homes right after the tornado hit; a second story of a house was taken off," Eddie Lavallie told the Chicago Tribune.
Streator Mayor Jimmie Lansford told a news conference that 17 people had been taken to a local hospital for treatment - and 30 buildings had "major structural damage".