Yellowstone National Park officials have opted to allow 720 snowmobiles a day in the park this winter, abandoning a temporary plan they proposed two weeks ago for 318 machines a day.

The National Park Service decision comes as a shock to conservation groups, which largely supported the temporary plan for 318 snowmobiles and 78 snow coaches a day, a level of use similar to the daily average during the past two years.

U.S. District Judge Clarence Brimmer on Nov. 7 reinstated the 2004 temporary rule that allows 720 snowmobiles after District Judge Emmet G. Sullivan in Washington, D.C., threw out a 2007 final plan earlier this year that would have allowed 540 snowmobiles a day in Yellowstone.

Yellowstone spokesman Al Nash said the park is trying to comply with Sullivan and Brimmer. Given the average daily use during the past two years, Nash said, snowmobile numbers in the park likely won’t come close to approaching the 720 maximum this winter. He said the park will still take comments on the temporary plan for 318 machines a day as part of the process to come up with a permanent plan.

“We haven’t prematurely stopped that process,” Nash said. “Both judges have given us direction to work towards some new long-term solution, and so it’s our intent to analyze those comments once they are received to help us determine what approach or approaches might be appropriate.”

For now, Nash said, reinstating the 2004 plan for 720 snowmobiles a day provides access for the start of this winter, which is scheduled for Dec. 15.

“Our goal all along has been to provide some certainty for our visitors, provide some certainty for our community and provide some certainty for our employees so they can plan for this winter,” he said. “We’re less than four weeks away from the start of this winter season.”

Tim Stevens, Yellowstone program manager for the National Parks Conservation Association, said the Park Service is choosing to misinterpret Brimmer’s ruling.

“It’s clearly an abdication of the Park Service’s responsibility to protect Yellowstone,” he said. “It flies in the face of that decision proposed just two weeks ago.”

“This just creates more problems and more uncertainty,” Stevens said. “They’re still acting like the gang who can’t shoot straight.”

Stevens wouldn’t rule out the possibility of filing an injunction against the 720 snowmobiles this winter.

“All options are on the table right now,” he said. “Certainly we are discussing any and all options that are available to us. The Park Service has lost its way in this process and somebody has to stand up for our nation’s first national park.”

People can comment on the now-defunct temporary plan for 318 snowmobiles through Nov. 20 at www.regulations.gov/search/index.jsp. The proposed rule is available by searching the “Documents Open For Public Comment” on the Web site and selecting the National Park Service as the agency.