One way or another, Yellowstone National Park will open for the winter season a week from today.

As of Wednesday there wasn't enough snow cover throughout the park to allow for over-snow travel, but officials were ready to permit wheeled travel for commercial vehicles if need be, said park spokesman Dan Hottle.

At Yellowstone Vacations, one of the concessionaires that travels the park in winter with both snowcoaches and snowmobiles, Randy Roberson said he's ready for opening day regardless of the state of the snowpack.

"In a nutshell, despite subpar snow, we’re ready to roll. Visitors will have access to Old Faithful no matter what amount of snow we receive over the next eight days," Mr. Roberson said Wednesday. "Rubber-track snowcoaches give us the flexibility -- which gives us certainty. When there isn’t adequate snow for access with snowmobiles or steel-track snowcoaches, we now have a much larger fleet of rubber-track snowcoaches that can operate in any snow conditions and ensure that the public gets to visit Yellowstone."

When there is plenty of snow for over-snow vehicles, the ground rules for snowmobiles and snowcoaches will be the same as they have been in recent years -- a maximum 318 snowmobiles and 78 snowcoaches per day will be allowed into the park. Those snowmobiles must be powered by the Best Available Technology, and commercially guided. Snowcoaches also must be commercially guided, but as of yet there's no requirement that they too, contain BAT engines.

While park officials had hoped to have a new over-snow plan in effect, Superintendent Dan Wenk in September said they need more time to finalize a sound, sustainable winter-use plan for the park and will continue for another winter of temporary guidelines while doing more studies.

For more than a decade, at a cost "in excess of $10 million," Yellowstone officials and staff have been trying to develop a feasible winter-use plan that suits both those in favor of recreational snowmobile use in the park and those who believe snowmobiles should be blocked from entering the park. Lawsuits, threats of them, and politics time and again have forced the park staff back to the drawing board.

The latest effort produced a Draft Envionmental Impact Statement of more than 550 pages with seven alternatives ranging from no over-snow visitor traffic in the winter to a variety of mixes of oversnow traffic. But problems with the underpinnings of those alternatives led the superintendent to call for more studies on items ranging from air quality and soundscapes to "best availability technology" requirements for snowcoaches and continued access over Sylvan Pass.

This past Monday the Park Service signed a Record of Decision on a plan that would keep the temporary guidelines in place for another winter.  Once the Record of Decision is published in the Federal Register, the Park Service will return to work on a Supplemental EIS that will contain the further analysis of the issues raised during the public comment period.

Among the unresolved questions Superintendent Wenk cited in September:

* He wanted to know how noise from snowmobiles and snowcoaches actually occurs. "What I’m asking is, is there a better way to look at the size of groups, how many snowmobiles should be allowed per group that enters, should we have snowmobiles travel in groups, or should we have them individually?" he said.

* More work is needed to determine the consequences of keeping Sylvan Pass safely open for over-snow traffic. “There were a lot of questions raised, and we need to do a further analysis of the impacts that are from the actions that we take on Sylvan Pass in terms of to bring down the avalanches," he said. "There were a lot of questions raised about the impacts on wildlife by those actions that we think we need to do further analysis. Whether that will change the outcome or not, I’m not making a predetermination on. But we believe that we have to have more analysis.”

* Park staff did not consider impacts on air quality and soundscapes using 2010 fleet data. "We did not use the right modeling, and so we are going to go back and fix that," the superintendent said.

* Park staff is uncertain whether sound levels prescribed for "best available technology" snowcoaches are achievable.

* The DEIS did not examine the impacts of allowing non-commercially guided snowmobile trips.

A draft Supplemental EIS is expected to be completed and released for public review and comment in 2012.  The National Park Service intends to have a final Supplemental EIS, a Record of Decision, and a long-term regulation in place prior to the start of the 2012-2013 winter season.