Freezing rain has closed some major roads in northern Alberta, cutting off the oilsands region of Fort McMurray from the south.
Mounties say rain falling on ice has forced the closure of Highway 63 between the Highway 55 junction and Secondary Highway 881.
Highway 55 is also closed between 63 and 881.
Hundreds of cars and trucks have been waiting at either end of the road blocks, hoping to get through.
Police say conditions are so bad that road crews are having trouble clearing a path.
Highways 63 and 881 are the ground routes in and out of the Fort McMurray area.