A political blizzard has descended on Yellowstone National Park.

After more than a year of legal wrangling, the park has decided to allow up to 720 snowmobiles into Yellowstone each day this winter, a move that startled park advocates. In 2007, a decade’s worth of Park Service research concluded that so many snowmobiles are incompatible with the preservation of Yellowstone’s natural resources.

“This decision was based on something other than science, law, and the views of the American public,” says Tim Stevens, NPCA’s Yellowstone program manager. “The Park Service has lost its way in this process.”

Last year in Washington, D.C., NPCA and other advocacy groups sued the Park Service in response to the Bush Administration’s proposal to allow 540 snowmobiles in Yellowstone each day—nearly twice the daily average of the past five years. The rule would have degraded air quality, tripled the area where visitors hear noisy engines, and increased stress on wildlife struggling to survive harsh conditions.

The judge ruled against the Administration, upholding the Organic Act and the Park Service’s own management policies, and ordered the Park Service to come up with a new plan. But the snowmobile industry filed a separate lawsuit in Wyoming, where a judge ruled that Yellowstone should stick to its daily allowance of 720 snowmobiles until it can draft a more suitable temporary plan. There was hope that the park might cap its daily limit at 318 snowmobiles this winter, but Yellowstone’s superintendent chose not to pursue a temporary plan at all, and defaulted instead to the upper limit of 720, a number that flies in the face of its own science.

For ten years now, more than half-a-million Americans have submitted comments about winter access in Yellowstone, and four out of five favor snowcoaches over snowmobiles. NPCA is considering further legal action, including an appeal to a higher district court.