There's no doubt about it - Yellowstone by snow machine is a kick. It's not only the ghost trees and clouds of steam around the hot springs, or the eyeball-to-eyeball encounters with big game.
It's also the sense of hurtling through icy air with nothing between you and instant death but a plastic windshield. We didn't see any yahoos chasing coyotes or tossing Schlitz cans into the drifts. David McCray, who rents 100 snow machines in West Yellowstone, reports that most of his customers are first-timers.
"You have to be here to see the levels of excitement a lot of these people come back with," he says. It's not uncommon for someone to tell him, "This was the best day of my life."
Then there's the down side. Packs of the machines leave a smelly haze on the road behind them. And a snowmobiler travels at the center of a shock wave of noise that seems perversely designed to destroy the wintry peace it traverses. The machine is so raucous you have to use hand signals even to communicate with your seat-mate.
I only learned after the trip that Park Service employees who use these machines are advised to wear ear plugs; 10 days later, my ears were still ringing.
Evidently unfazed by the din, the bison we encountered moved aside - if they moved at all - with stolid indifference. Park employees have noticed, however, that they use the groomed roads mainly at night, when the over-snow traffic almost stops. Since bison are not nocturnal animals, this fact speaks volumes about their preferences.
Yellowstone planner John Sacklin hopes that an environmentally friendly Yellowstone snowmobile can soon be created, something "whisper-quiet, that produces virtually no emissions." In the meantime, the old environmentally unfriendly variety is what's seen - and heard "everywhere.
"What can you say?" a gas station attendant here told me. "They're noisy and they stink."
* Lynne Bama