Yellowstone National Park – So far this winter, there's been a spike in the number of snowmobiles that have visited Yellowstone. Park officials say the number increased by more than 12 percent for the period of December-through-February, as compared to the same period last year. Yellowstone spokesman Al Nash says the reason might be that people have been able to plan their trips because the winter use rules have been stable. "We've been operating under temporary rules now for three winters. That provides visitors some consistency and certainty about their ability to visit the interior of Yellowstone in the winter." But those rules could be changing again. The Park's been working on a new winter use plan. A draft of the plan is due to come out at the end of the month.