• A bull elk bugles in Yellowstone National Park

    Yellowstone

    National Park ID,MT,WY

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  • Craig Pass Closed for the Season; Mammoth to Norris Closed Sept. 14-30

    The road linking West Thumb and Old Faithful is closed for the season—traffic should detour through West Thumb, Lake, and Canyon. The road from Mammoth to Norris is closed for two weeks—traffic should detour over Dunraven Pass. More »

Sylvan Pass Winter Status

Park staff use a howitzer to reduce avalanche danger.

Park staff use a howitzer to reduce avalanche danger.

Sylvan Pass Winter Travel

The park's East Entrance road crosses 20 avalanche paths through Sylvan Pass.

Yellowstone has been conducting avalanche hazard mitigation operations at Sylvan Pass since 1973. The final rule implementing the long-term plan to guide management of winter use in Yellowstone calls for Sylvan Pass to remain open to motorized oversnow travel.

The park is using a combined helicopter and howitzer program to conduct avalanche hazard mitigation operations this winter on Sylvan Pass. Rangers monitor weather and snow conditions and review a wide range of data to aid them in forecasting the avalanche danger for Sylvan Pass.

Some sources of the data include the following web sites:

Sylvan Pass may be temporarily closed to all travel when avalanche forecasting shows travel is unsafe. It will remain closed until forecast conditions permit Yellowstone National Park employees to conduct avalanche hazard mitigation operations and groom the route for motorized oversnow travel.

Methods used to reduce the risk of avalanche hazard mitigation this winter may result in longer temporary closures between the detection of avalanche risk and the reopening of Sylvan Pass to motorized oversnow travel compared to historic avalanche hazard mitigation operations.

See Current Conditions and Updates for other related seasonal information.

Did You Know?

Seventh Cavalry Ensignia Pin.

Prior to the establishment of the National Park Service, the U.S. Army protected Yellowstone between 1886 and 1918. Fort Yellowstone was established at Mammoth Hot Springs for that purpose.