Yellowstone plan would leave gates open to snowmobiles

Despite the conclusions from its own scientists that snowmobiles in Yellowstone National Park continue to create unacceptable noise levels, the National Park Service released a draft plan Monday that would allow up to 720 snow machines in the park per day.

The plan would maintain the current maximum daily numbers, or about three times as many snowmobiles as entered the park each day over the last three winters. The snowmobiles must use what the Park Service calls “best available technology” to reduce noise and pollution levels.

The park service is in the middle of the fourth extensive scientific analysis of the impact of snowmobiles at Yellowstone. These followed a Bush administration reversal of a Clinton-era phaseout of snowmobiles that cited visitor and employee health and enjoyment as well as the welfare of wildlife in the park.

The previous reports, which have cost more than $8 million, have all concluded that snowmobiles result in unhealthful air and unacceptable noise. The park service is considering a range of options, from banning snowmobiles in favor of snow coaches (multi-passenger vans mounted on treads) to its preferred alternative, setting a daily limit on snowmobiles and requiring that tours be guided by someone with specialized training.

The plan announced Monday -- which has not been finalized -- would also allow 140 snowmobiles a day to enter Grand Teton National Park and the John D. Rockefeller Jr. Memorial Parkway connecting the two parks.

The Environmental Protection Agency and other federal agencies have concurred with the park service’s past call for a policy replacing snowmobiles with commercial snow coach tours as the sole motorized access to the park during winter.

Park officials point out that air quality has much improved in the Yellowstone region since the new rules went into effect. But the improvement has occurred during years when snowmobile use has averaged about a third of the maximum number allowed -- and as a growing number of visitors have chosen to tour the park in snow coaches.

A report released this month by the park service’s air resources division concluded, “Most of the gain in air quality can be attributed to the smaller number of snowmobiles.”

Though the park now requires snowmobiles to utilize a newly designed four-stroke engine, the technology has not restored the standard for natural quiet required by park service regulations. Monitoring over three years has shown that the machines have been exceeding noise standards both for decibels and for the percentage of time the machines are heard throughout the park.

According to park service studies, the cleaner and quieter snow machines can be heard in about twice as much of the park as snow coaches.

In past winters, rangers at entrance stations have been advised by park officials to wear hearing protection.

“The backdrop to this announcement is that Yellowstone has a noise problem with 250 snowmobiles a day,” said Jon Catton, a Montana-based conservationist. “Their studies show that snowmobiles are frequently interfering with visitors’ opportunity to hear and enjoy wildlife and other sounds that make Yellowstone special.”

Wyoming Sen. Craig Thomas, the Republican chairman of the Senate subcommittee on national parks, said in a statement, “As with any plan that considers competing points of view, it’s not perfect, but I’m pleased that our public land managers recognize the importance of maintaining visitor access to our national parks in Wyoming.”

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julie.cart@latimes.com