WASHINGTON – Snowmobiles could continue using Yellowstone and Grand Teton national parks for at least the next three winters under a federal proposal to be released Thursday.

The plan by the National Park Service is meant to buy time until a more permanent solution to snowmobiling use at those parks can be found, said Al Nash, a Park Service spokesman in Mammoth Hot Springs, Wyo.

“What we’re trying to do is come up with an appropriate plan for up to three winters that will allow people to know what to expect and will allow us some time to gather some more information,” Nash told The Associated Press.

Nash said that “strictly limited snowmobile and snow coach use” would be allowed during the three years.

Local businesses and snowmobile makers want snowmobiling to continue around the parks. They argue that they deserve access and that new machines are cleaner and quieter than older models.

But federal courts in Wyoming and Washington, D.C. are still weighing legal disputes over whether snowmobiles should be allowed. It also has become an election-year issue between environmental and economic interests.

The Park Service also will propose a separate rule that regulates winter use during the three-year grace period, Nash said. The public will have 30 days to comment on the plans. The final rule for the grace period is to be made final in late October.

In February, the Park Service, responding to a Wyoming judge, proposed increasing from 493 to 780 the number of snowmobiles allowed in Yellowstone each day. The Clinton administration in 2000 had made plans to phase out the snowmobiles and replace them with mass-transit snow coaches.

The Coalition of Concerned National Park Service Retirees predicted the plan to be announced Thursday would more than double snowmobile use in Yellowstone National Park, which straddles the northwestern corner of Wyoming and parts of Montana and Idaho.

The group cited two former Yellowstone park superintendents, Michael Finley and Rick Smith, who both warned that the administration’s plan would put special interests ahead of science.

Nash said the Park Service anticipates its latest plan will not significantly harm the environment or public health. He declined to provide more details, saying the document would not be finished until Thursday.

An earlier draft of the “temporary winter use plans environmental assessment” was 200 pages long.

The plan also will affect Grand Teton National Park in Wyoming, just to the south of Yellowstone, and the John D. Rockefeller Jr. Memorial Parkway that connects the parks.

“We felt like the best way for us to move forward would be for us to create a temporary plan that would give some measure of certainty,” Nash said.

“We’re looking at this as a way to come up with permanent regulations,” he said. “We don’t know what a final plan will be since it’s very hard for us to know what our analysis of data will show.”

In June, the House voted to allow snowmobiling to continue in the parks. Its vote, 224-198, defeated an effort to ban the vehicles by lawmakers who said the machines cause pollution and noise, and pose a danger to the parks’ wildlife.