Yellowstone National Park's winter season begins this week.
The nation's oldest national park opens for commercially guided snowmobile and snowcoach trips on Tuesday, Dec. 15.
Al Nash is spokesman for Yellowstone. He says it's common for snow levels to be low early in the winter season. In some years he says the park has to open using a combination of wheeled vehicles and tracked vehicles such as snowmobiles.
Snowmobile traffic at the park this winter and next will be limited to 318 machines a day under an interim rule adopted by the U.S. Park Service. That's fewer than half the limit of the past few years.
Wyoming and Park County are challenging the new limits in court, but haven't asked for any emergency court action to raise the limit.