Yellowstone snowmobiles

Snowmobilers ride in Yellowstone National Park in this Dec. 21, 2017 photo.

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A proposal to extend seasonal access for snowmobiles and snow coaches at the east entrance of Yellowstone National Park is up for public comment, with park officials convinced they can safely handle avalanche hazards around Sylvan Pass.

If the adjustments to the park’s Winter Use Rule are approved, the entrance near Cody, Wyoming, would open no earlier than Dec. 15 and close no later than March 15.

Since 2007, officials have kept the entrance closed between Dec. 15 and 21 and between March 2 and 15 to limit safety risks posed by avalanches on Sylvan Pass. The high-elevation mountain pass crosses over the Absaroka Range.

“This change will standardize opening and closing dates for the entire park,” Yellowstone officials wrote.

A second proposed modification would authorize opening the park’s south entrance near Jackson, Wyoming, at 8 a.m. instead of 7 a.m. Opening an hour later would give National Park staff time to assess road conditions before operators leave Jackson, officials wrote.

People can comment on the adjustments to the park’s Winter Use Plan until Oct. 29.

In 2007, the National Park Service conducted an avalanche hazard assessment and mitigation report to identify safety concerns on the pass. At the time, six avalanche fatalities had been reported in the area, according to the report.

Now that the park has used the closures for years and improved operational capacity and expertise, officials announced they can consider extending the season.

In the winter, 46 commercially guided snowmobiles and four non-commercially guided snowmobiles are allowed to enter the park per day. Up to 110 “transportation events” can occur in a day.

Officials have limited the number of snowmobilers and snow coaches allowed to enter the park in a day, with rules implemented in 2013. The rules were added after the National Park Service faced a series of lawsuits over the impacts of winter travel on bison and other species.

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Helena Dore can be reached at or at 582-2628.

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