An avalanche has closed Highway 200 about a half-mile east of Helmville after sliding onto two vehicles.
The Missoula County Sheriff's Office said it had received no requests for assistance after the slide dumped six to seven feet of snow on the highway at mile marker 56 near the intersection with Highway 141 about 9 p.m. Friday.
A social media post from Lincoln Volunteer Fire Rescue urged people to "Stay home. It's bad. Very. No joke folks.''
Missoula County Undersheriff Rich Maricelli said one of the cars was traveling east, the other was heading west when the avalanche struck them but had no information on the conditions of the occupants or whether the vehicles had been damaged.
Powell County officials could not be reached for details Friday night.
The Montana Department of Transportation said westbound traffic on Highway 200 was being detoured at Lincoln and eastbound traffic will be detoured onto Highway 141.