Only recently have noncommercial snowmobile outings been reintroduced into Yellowstone. Obtaining a permit is incredibly difficult: Only one group of five or fewer snowmobiles is allowed to enter from each of the park’s four entrances per day. If you manage to snag a permit, you can experience the park at your own speed (provided that speed is 35 miles per hour or less; that’s the speed limit throughout the park) and with your own itinerary. It’s possible to travel the glistening snowscape for hours without seeing another human. If you can’t get a permit, numerous commercial outfitters (in West Yellowstone, Jackson, or Cody) run group snowmobile trips into the park.