The Superintendent of Denali National Park and Preserve has determined that there is not adequate snow cover for the use of snowmobile for traditional activities in the 1980 additions to Denali National Park and Preserve on both sides of the Alaska Range. 

All park lands that were open for snowmobile use are now closed for the season. 

All lands within the former Mount McKinley National Park on both the north and the south sides of the Alaska Range are closed to all snowmobile use by federal regulation. 

Original source can be found here