Pick sixIn the future, snowmobiling in Yellowstone National Park could be eliminated entirely, kept at similar levels to recent years or be expanded to previous limits.Park Service officials on Thursday unveiled the six alternatives they plan to study in coming months as they draft an environmental impact statement for Yellowstone's winter use plan. The alternatives range from phasing out all snowmobiles to allowing up to 720 per day and include an option to plow the park's western roads and close the East Entrance to all over-snow vehicles.

To date, coming up with a lasting winter use plan has proven elusive, with three previous plans having been voided by federal judges over pro- and anti-snowmobiling group lawsuits.

The Park Service's last attempt at a winter plan initially called for closing the East Entrance, but local residents and government officials protested and got the Park Service to agree to keep it open on a slightly shorter winter season.

Winter use in the park is currently guided by a temporary plan set to expire at the end of the 2011-2012 season; it allows up to 318 snowmobiles and 78 snowcoaches and provides East Entrance management.

Going forward, the Park Service has identified the following alternatives for managing winter use in Yellowstone:

• Taking no action — This alternative, unlikely to be chosen, would have the Park Service create no plan and allow only non-motorized access (skiing, snowshoeing, etc.) into Yellowstone in the winter.

• Continue use at current levels — This alternative would continue to allow up to 318 snowmobiles and 78 snowcoaches into the park per day. All over-snow vehicles would continue to be required to be led by licensed commercial guides and meet best available technology requirements.

• Returning snowmobile limits to higher levels — Snowmobile limits would be boosted to a 2004-plan limit of 720 sleds per day, with up to 78 snowcoaches. Guiding and best technology requirements would continue.

• Creating a mixed-use system — Under this alternative, the Park Service would begin plowing the road from West Yellowstone and Mammoth Hot Springs to Old Faithful, allowing access to commercially-licensed buses and vans. The South Entrance would allow up to 30 snowcoaches and 100 snowmobiles per day, while the East Entrance road over Sylvan Pass would be closed to snowmobiles and coaches. Skiing and other non-motorized access would continue at the East Entrance. (The road from the North Entrance to Cooke City is currently plowed year-round and there are no alternatives that would change that setup.)

• Transitioning to snowcoaches only — Initially up to 318 snowmobiles and 78 snowcoaches would continue to be allowed each day. But beginning in the 2014-15 winter season, snowmobile use would be phased out within a five-year period; daily snowcoach limits would increase as snowmobile limits dropped.

• Varying limits and usage — The Park Service would allow varying levels of use depending on the time and place. Park County commissioners have long pushed for snowmobile limits that can rise for the most popular days of the winter; in a newsletter, the Park Service gives the example of undisturbed skiing and snowshoeing times. Up to 32,000 snowmobiles and 4,600 snowcoaches would be allowed to enter the park each winter, with a daily maximum of up to 540 snowmobiles and 78 snowcoaches. Additionally, up to 25 percent of snowmobilers would be allowed to enter the park without a commercial guide.

In most planning processes under the National Environmental Policy Act, little information is released between the scoping period and the release of the draft environmental impact statement. But in the case of winter use in Yellowstone, officials felt it was important to let the public know what alternatives the Park Service will be analyzing, said Yellowstone Park spokesman Al Nash.

“We realize this is of great interest to a large number of people. We're looking to let people know where we are in the planning process every step of the way,” Nash said.

During the public scoping period earlier this year, the Park Service received nearly 9,100 pieces of correspondence from across the United States. The vast majority — some 7,400 submissions — were form letters gathered and submitted by several organizations, a Park Service scoping comment summary says.

Around 7,000 of the form letters came mostly from anonymous individuals advocating for a snowcoach-only plan, the summary indicates.

The six alternatives chosen by the Park Service were based on the public comments received.