Fremont County Emergency Management Director Mike Crecelius told The Associated Press on Saturday that about 75 percent of the town of Thurman was destroyed.
He said there were no injuries and no deaths in the town of about 250 people.
Crecelius said the town was on lockdown Saturday night and wasn't letting anyone in. He said town officials and residents expect to start cleaning up on Sunday.
Crecelius said some residents had taken refuge in City Hall, which was the only building in town with power. Others were staying in a shelter, at motels or with relatives.