A federal judge, ruling that Yellowstone National Park's decision to continue recreational snowmobile use in the park runs counter to science and the National Park Service's conservation mission, has tossed out the park's winter-use plan.

U.S. District Judge Emmet Sullivan's ruling, while sure to spur more legal battles, throws in doubt whether there will be recreational snowmobiling in Yellowstone and Grand Teton national parks when the winter season gets under way in mid-December.

"We've got to figure out what it means. We don't know where we go from here," Yellowstone spokesman Al Nash said this afternoon. "The judge was very clear that he took issue with some of our analysis and decision-making. It's up to our winter-use planning staff and Justice Department attorneys to study this so we know how to move forward."

In his 63-page ruling, which was stinging at times in its criticism of the Park Service's interpretation of its own Organic Act, Judge Sullivan held that while the Organic Act does call for public enjoyment of the national parks, "(T)his is not blanket permission to have fun in the parks in any way the NPS sees fit."

"As plaintiffs articulated at the hearing, the 'enjoyment' referenced in the Organic Act is not enjoyment for its own sake, or even enjoyment of the parks generally, but rather the enjoyment of 'the scenery and natural and historic objects and wild life' in the parks in a manner that will allow future generations to enjoy them as well," wrote Judge Sullivan in today's ruling. "NPS cannot circumvent this limitation through conclusory declarations that certain adverse impacts are acceptable, without explaining why those impacts are necessary and appropriate to fulfill the purposes of the park."

The winter-use plan was challenged by the Greater Yellowstone Coalition, the National Parks Conservation Association, the Sierra Club, The Wilderness Society, the Winter Wildlands Alliance, and the Natural Resources Defense Council.

“This ruling reaffirms the idea at the heart of our National Park System—that the duty of Yellowstone’s managers is to preserve the park for the sake of all visitors, and to place the highest value on protection of Yellowstone’s unique natural treasures,” said Tim Stevens, senior Yellowstone Program Manager for NPCA.

“This ruling will ensure that visitors are not disappointed by air and noise pollution when they make the one winter trip to Yellowstone of their lives,” said Amy McNamara, National Parks Program Director for the Greater Yellowstone Coalition. “We take our hats off to the tour businesses that didn’t wait for this ruling. Their increasing investments in modern snowcoaches are already making it possible for winter visitors to access and enjoy Yellowstone while protecting it.”

At the Coalition of National Park Service Retirees, leaders were calling for Yellowstone and National Park Service officials to accept the judge's ruling and work harder to protect the parks' resources.

"They should be quietly praising this whole thing instead of continuing to obfuscate the whole question in my judgment," said Bill Wade, who chairs the coalition's executive council. "It should be very clear where they go from here.”

Mr. Wade said Yellowstone Superintendent Suzanne Lewis should have the authority to pass an emergency rule to allow a limited amount of snowmobiling in the park this year while her staff moves to develop a winter-use plan in line with Judge Sullivan's ruling.

That said, the coalition believes snowcoaches -- not snowmobiles -- should transport winter visitors in Yellowstone because the coaches are safe, quieter, less polluting, and less impacting to wildlife than snowmobiles.

During the past 11 years the Yellowstone snowmobiling saga has seesawed back and forth. While the Clinton administration on its way out of office issued a directive that snowmobile use be phased out of the park, the Bush administration immediately stayed that when it took office.

A series of legal challenges -- some by conservation groups, some by snowmobile advocates such as the International Snowmobile Manufacturers Association -- alternately pulled the Park Service in opposite directions. The latest decision came last November, when Yellowstone officials approved a plan to allow up to 540 snowmobiles and 83 snowcoaches per day into the park -- despite research that concluded such levels would impact park resources.

When the coalition of conservation groups announced its legal challenge to the plan, it noted that the Park Service disclosed in a study accompanying its decision that allowing 540 snowmobiles into Yellowstone each day would dramatically expand to 63 square miles-the portion of the park where visitors could expect to hear snowmobile noise during more than half of the visiting day. That would be a three-fold increase from the current portion of the park where noise intrudes on the visitor’s experience during at least half the day.

The groups also noted that in its Final Environmental Impact Study accompanying its decision, the Park Service acknowledged that Congress established the National Park Service in 1916 in part due to a recognition that the American people “wanted places to go that were undisturbed and natural and which offered a retreat from the rigors and stresses of everyday life.”

Judge Sullivan found more than a few problems with the National Park Service's conclusions in approving the winter-use plan (WUP). Among them:

* The court finds that NPS fails to articulate why the WUP's impacts are 'acceptable.' NPS simply repeats the above standards in the context of the WUP's impacts on soundscapes, wildlife, and air quality, but fails to provide any supporting analysis of how the impacts relate to those standards.

* The ROD (record of decision) makes no effort to explain, for example, why impacts on soundscapes characterized as 'major and adverse' do not 'unreasonably interfere with the soundscape' and cause an unacceptable impact.

* Similarly, NPS fails to explain why increasing the amount of benzene and formaldehyde to levels that broach (and sometimes exceed) the minimum risk levels applicable to hazardous waste sites does not 'create an unsafe or unhealthful environment for visitors or employees.'

* ... NPS provides no quantitative standard or qualitative analysis to support its conclusions that the adverse impacts of the WUP are 'acceptable.'

* As with soundscapes and wildlife, the court finds that NPS has failed to articulate why a plan that will admittedly worsen air quality complies with the conservation mandate.

In his conclusion, Judge Sullivan found that the winter-use plan "clearly elevates use over conservation of park resources and values and fails to articulate why the plan's 'major adverse impacts' are 'necessary and appropriate to fulfill the purposes of the park."

"NPS fails to explain how increasing snowmobile usage over current conditions, where adaptive management thresholds are already being exceeded, complies with the conservation mandate of the Organic Act," he wrote.

While this ruling was being digested today, Yellowstone's winter-use planners were joined by Department of Justice attorneys in Cheyenne, Wyoming, before U.S. District Judge Clarence Brimmer. Judge Brimmer, who in the past has ruled almost completely opposite Judge Sullivan on the snowmobile issue, was conducting a hearing into a lawsuit brought by the state of Wyoming and Park County, Wyoming, over the winter-use plan's 540-snowmobile-per-day limit as well as its requirement that snowmobilers be led by commercial guides.