During Yellowstone [1]’s first 75 years as a park, winter visitation was almost unknown. The only people in the park were caretakers, who spent months at a time with no contact with the world outside.
This began to change in 1949, when snow-plane tours were first offered from the West Entrance. The planes skimmed over the surface and could hold only two people—the driver and a passenger—so visitation barely topped 30 people that winter.
In 1955, snowcoaches [2] were permitted to enter Yellowstone, and more than 500 people visited, although few stayed overnight.
The first snowmobilers arrived in 1963, when the machines were still a novelty. As snowmobiling became increasingly popular, communities around Yellowstone benefited economically and began promoting the park as a winter wonderland. In the winter of 1971-1972 the Park Service began encouraging snowmobile use by grooming the roads and opening Old Faithful Snow Lodge.
By the end of that winter, more than 25,000 people had visited, and by the early 1990s the number had rocketed to more than 140,000 people, with the park admitting more snowmobiles than all other national parks combined. Noise and air pollution from the two-cycle engines became a serious problem as 1,600 snowmobiles flooded into Yellowstone on busy days.
In the heavy-snow winter of 1996-1997 large numbers of bison moved out of Yellowstone, some of them along the groomed snowmobile road out the west side of the park. Nearly 1,100 bison were killed that year as part of Montana’s effort to protect cattle from brucellosis (bison use the groomed-for-snowmobiling roads to find their way out of the park, potentially carrying brucellosis to cattle on surrounding ranches).
The slaughter precipitated a lawsuit by the Fund for Animals that forced the Park Service to rethink its winter-use policies. To address the effects of snowmobiles and other uses, the Park Service under President Clinton attempted to ban snowmobiles from the park. Industry groups and others successfully fought the closure, with support from the snowmobile-friendly Bush administration.
After a decade of heated debate, the Park Service adopted a new winter use plan in 2007 that allows a maximum of 540 snowmobiles and 83 snowcoaches per day. All snowmobiles must be commercially guided and meet best-available emission and noise requirements (i.e., four-stroke engines). The new rules have significantly reduced snowmobile trips into the park.
Snowmobiles are available for rent from all four sides of the park and inside Yellowstone at Mammoth [3] and Old Faithful [4], with the majority of snowmobilers—all guided, of course—coming in from West Yellowstone, where prices are usually a bit lower and access is quicker. Contact chamber of commerce offices in West Yellowstone or Jackson for companies offering snowmobile tours.
Links:
[1] http://www.moon.com/destinations/yellowstone-grand-teton/yellowstone-national-park
[2] http://www.moon.com/destinations/yellowstone-grand-teton/yellowstone-national-park/winter-recreation/snowcoaches
[3] http://www.moon.com/destinations/yellowstone-grand-teton/yellowstone-national-park/sights/mammoth-hot-springs
[4] http://www.moon.com/destinations/yellowstone-grand-teton/yellowstone-national-park/sights/old-faithful-and-upper-geyser-basin