Yellowstone’s West, South and East entrances will close to vehicle traffic at 8 a.m. Monday.
The North Entrance road, which connects Gardiner and Mammoth to Cooke City and Silver Gate, Montana, via Lamar Valley, remains open year-round.
In the 11 days following the closure of Yellowstone interior roads, crews will be grooming the routes to prepare them for snowmobile and snow coach travel. The winter season starts Dec. 15 and will run through early March.
Several road closures took effect in Grand Teton National Park on Friday. Teton Park Road is now closed between the Taggart Lake trailhead and Signal Mountain Lodge.
Moose-Wilson Road closed to motorized vehicles between the Death and Granite canyon trailheads.
Antelope Flats, Deadmans Bar, Grassy Lake, Pilgrim Creek, Schwabacher and Two Ocean roads will close for the season based on conditions.