Getting your Trinity Audio player ready...

I had booked a guided tour requiring the only sort of vehicle allowed in Yellowstone National Park during winter-something with skis on it-and I had very little idea what that would entail.

Brochures for the 11 companies in the Jackson Hole area that run such expeditions are stingy with details. And colorful but office-bound Llama Louie, the tour-booking agent in Teton Village, was equally cryptic.

”You`ll be picked up in the lobby of your hotel at 7:30 sharp,” he said. ”You have a scarf? Good. That`s all you`ll need.” He handed me a receipt for the $135 I had paid.

Guide Bob Lowe, owner of Best Adventures, picked me up the next day in his big, beige van. The vicissitudes of Jackson Hole tourism last month-blame the recession, the lack of snow-had left him with no customers but me that morning.

We drove a few blocks to his office, space rented from a summer-only service station, and Lowe gestured toward a small table holding a coffee pot and a jug of orange juice.

”Grab whatever you want,” he said. So much for the ”free continental breakfast” touted in the Best Adventures leaflet.

He asked my shoe size, looked at me appraisingly and brought over felt-lined boots, a black snowmobile suit and a thick plastic helmet. All fit, and suddenly I felt more like Darth Vader than a mountaineer.

During the 45-minute drive from Jackson to Flagg Ranch, the snowmobile staging area here, Lowe told me he was 35 (tall, blond and ruddy, he looked a decade younger), divorced, a graduate of the University of Wyoming and owner of the business for the last three years. In the summer he leads horseback rides and fishing trips.

”I never get tired of looking at this,” Lowe said, gesturing out the van window at the Tetons off to our left. They glowed with surreal splendor in the sunshine. Moments later we saw a moose grazing on the Gros Ventre Range to our right. And when the plowed road came to a halt, it was exciting to anticipate that we would keep going over the groomed snow trails that cover the park highway to a 5-foot depth.

All aboard

First, however, I would have to climb aboard a new and strange form of transportation, the Ski-Doo Safari LE, one of two that Lowe had unloaded from the trailer in back.

”You`ll be a pro in no time,” he assured me, pointing out the orange button that would fire the snowmobile`s ignition and the handgrip that controls the throttle.

He said no more for quite a while after that. Both of us were held incommunicado by our thick, constantly vibrating helmets, the scarves that covered our mouths and the sheer concentration required to flog a heavy machine 45 miles an hour on a winding, uphill route.

My thumb mashed painfully against the accelerator lever as I tried desperately to keep up. I didn`t dare take my eyes off Lowe`s quickly receding red jacket or loosen my grip on the handlebars. The two miles from Flagg Ranch to the Yellowstone South Gate had all the serendipity of a slalom race, a hurtling passage through a white chute. It was thrilling, but hardly edifying. After a dozen miles, Lowe crooked his left arm, signaling a stop, and we dismounted at a scenic juncture of the Lewis River Canyon, where we could survey a vista of water and hills that would have been impossible to see before the fires of 1988.

”Those are the dead trunks of lodgepole pines,” he said, gesturing toward the charred forest.

”It will take 20 years for them to fall over. You can see the new growth starting to come up. The cones from those trees have to be heated to 200 degrees before they germinate, so in that sense the park needs fires. A lot of wildflowers cover these valleys in spring and summer-flowers like I`d never seen before. The ash really improved the fertility of the soil.

”A lot of people looked at the fire as a disaster, but I don`t see it that way. A fire like this might happen every 200 to 400 years, and it brings new life. Besides, the park covers 2.2 million acres, and just 600,000 acres burned.”

A view with lots of room

Despite that continental-breakfast size view of the big fire controversy, the dimensions and mystery of Yellowstone did seem overwhelming. Lowe stood there expectantly, and I felt obligated to take photographs and make appreciative comments. It was the first of several awkward moments. I was getting confused. Was this a reverent exploration of Yellowstone National Park or a desperate motocross? Were we communing with nature or maurauding like crazed Hell`s Angels?

Strangely, I felt an urge to move on, which we did as soon as I realized Lowe would be letting me decide when I had drunk in beauty enough.

Over the next few miles I gave myself to the odd pleasure of commanding a powerful machine. I forgot about the halftrack that propelled this monster and the skis up front connected to the handlebars. The Ski-Doo became a motorcycle, and for the first time in my life, I could begin to comprehend the forces that draw people to make long runs on a Harley-Davidson.

Without warning, Lowe disappeared into a thick fog, and when I saw him again he was signaling a stop outside a small cabin. The sign on it, ”Warming Hut,” was barely visible in the mist.

Two other snowmobiles were parked in front, and inside, a handful of people milled around a pot-bellied stove. My feet were numb. A map on the wall told me we had reached the portion of Yellowstone Lake called West Thumb. My east thumb, the one on my right hand, ached from pressing the throttle.

From the warming hut to the eastern shore, Yellowstone Lake covers 14 miles, filling in a portion of the mouth of the dormant volcano that is Yellowstone National Park. The lake`s north-south dimensions stretch another 20 miles. All that fog enshrouding us came from geysers steaming in the cold air. A thermometer outside the window registered minus 4 degrees Farenheit.

”We`ll take a look at this later,” Lowe promised as we zipped up our coveralls. Look at what? I thought.

The trip had begun to develop a manic rhythm as we headed west on the Grand Loop Road and over the Continental Divide. At unexpected moments Lowe would signal a stop, and we would walk to a vantage point. At one of them, small geysers known as paint pots gurgled colorfully in a flat canyon, splashing yellow, blue, green and brown minerals over the snow. We watched the Kepler Cascade pour into the miniature canyon cut by Nez Perce Creek. We looked at grazing bison and meandering elk.

At lunch time we pulled into a parking lot near Old Faithful. Lowe unhitched his saddle bags and led the way toward a picnic shelter.

”The ranger station said the next eruption will take place at 1:08,” he announced, producing two cardboard boxes filled with submarine sandwiches, cookies and juice.

”A lunch is served while waiting for the eruption of Old Faithful geyser,” his promotional literature had promised, truthfully enough. Had I expected something like fresh brook trout and venison? Well, yes.

As we ate, Lowe explained the intricacies of geyser construction, the labyrinth of rocky pipes that allows the water from rain and snow to seep far below the surface, where molten rocks create enormous steam pressure. When the pressure builds enough, the reservoir near the surface overflows and finally erupts. Old Faithful does this approximately every 40 minutes to an hour and a half.

As Lowe and I talked, a relentless buzz filled the air. Eruption time neared, and when we emerged from the pavilion, the lot was packed with snowmobiles and people in snowmobile suits.

The crowd formed a lengthy half-circle near the geyser and watched it splash in ever greater waves until it culminated in the great gusher, a break in the Earth emphasizing what a thin crust it is we live on.

That thought stayed with me as we drove farther north through the Upper Geyser Basin and as we stopped to gaze upon the beauty of Firehole Lake. Everything-waters, trees, geysers, mountains-looked cosmically temporary now. At last I felt I could begin to enjoy Yellowstone on its own terms. Enough time spent with a snowmobile demystifies the machinery, and then it`s possible to look around and drive simultaneously.

We began working our way back, and when we reached West Thumb again, it had lost its hazy mantle, revealing a glorious expanse of lake and shoreline, outlined by trees wearing halos of hoarfrost. Lowe and I strolled along the wooden walkways put up to keep visitors from scalding themselves in the calderas.

In another hour, which included a few more scenic pauses, we arrived at Flagg Ranch just moments before the other snowmobile tour groups come buzzing in. They looked the way I felt-saddlesore, thumb-weary, dazzled and slightly bemused.