Atop the Grand Teton. Wyoming's Exum school takes adventurers to lofty heights and teaches them to master mountains

GARY WAITE, a farmer from Missouri, hangs by his fingertips from a narrow ledge 12,000 feet above sea level. He has a rope around his waist and an expert climber on the other end of the rope to stop him if he starts to fall. Clutching the wall, Mr. Waite can see the sun splaying off the sea-green lakes in the valley below and a cluster of tents that now appear as splotches of yellow and red on the horizon.

He moves up the mountain slowly, slipping his hand over an outcropping of rock to reach a granite slab where instructor David Carman is waiting. He gulps down his reward - a granola bar and a few mouthfuls of a cold drink - and we take positions to continue up this 13,770-foot mountain.

There are many ways to see western Wyoming's Tetons: from your car, from the airplanes that soar overhead on their way to Jackson Hole, or from the lodges in Grand Teton National Park. But some people choose to see them up close and, more important, to overcome them - to stand on top and know that it took something extraordinary, possibly even obsessive, to make it to the summit.

Climbing is not for just anyone who feels the allure of these craggy peaks. But for people in good condition who delight in overcoming obstacles and their own fears, climbing the Grand Teton can be the ultimate thrill, one that stays with you for a lifetime.

Today Mr. Carman, a guide from the Exum Guide Service and School of American Mountaineering, based at Jenny Lake in the park, is charged with escorting me and Mr. Waite, who is 38 years old and returning for his fourth ascent up the Grand Teton. A 20-year veteran of climbing, Mr. Carman is no stranger to the mountain, having completed the first winter ascent of its north ridge some years ago. This morning he decides to delay the climb until the sun can melt snow from last night's storm on the mountain's southern face.

What makes these mountains so dramatic is that they rise so sharply, shooting up from the flat valley floor. Mountaineers from around the world come to try their skills on these famous peaks.

The physical demands on a climber are tough; it helps to train before attempting the climb. Still, Carman enjoys regaling his clients with stories of Harry, the 71-year-old former electrician from St. Louis who has scaled half a dozen Teton peaks with Carman in the lead.

Climbing the Grand Teton is the crowning accomplishment for most Exum graduates, coming usually after two days of practice on the rocks above Jenny Lake. The service's guides take nearly 300 climbers up the mountain every summer and instruct twice that many in daily rock-climbing classes on the boulders and low-sloping walls in the shadow of the Tetons.

But climbers also learn from the other climbers they meet on the mountain and at the base camp. Every Exum student spends the night before climbing the Grand Teton in the school's permanent hut at the base of the mountain. They usually share that camp with some of the guides.

The storm that blew over our camp the previous night forged a bond among the guides and their clients. As the lightning crashed outside, striking the nearby mountains, the veteran climbers swapped tales of climbing in Nepal and China. And they joked about the storm that rocked the vinyl hut throughout the night, dumping rain, hail, and then snow.

``Has anyone noticed the tent is glowing?'' quipped Jack Tackle, as a lightning bolt found its mark not too far away. Mr. Tackle had just returned from a wintry attempt on Alaska's fierce Mount Hunter. He and another climber spent a month in a tent waiting for a snowstorm to subside.

The jokes then turned to climbing. Rick Black, a veteran Teton climber and venture capitalist who was returning to scale routes he first climbed 10 years ago, advised us: ``You never talk bad about your partner when he's on the other side of the rope.''

Next morning, the weather broke at 10 a.m. The sun appeared and began to warm the southern face of the mountain. Carman was still worried about slippery snow and ice on the mountain as we left the base to start our climb.

We made slow but steady progress. Carman took us up a moderately difficult route, because Waite and I had both had some experience climbing. But the experience didn't take away the thrill - the awareness of being so high and of getting there yourself.

We were reminded of the dangers of mountain climbing the previous day as we hiked up the trail to the base camp. At Garnet Canyon, we met a shaken climber who had fallen and was limping past us to the trailhead below. He related the story of his slip down a patch of ice onto a field of boulders.

There are risks in climbing, but it all seemed worth it as we approached the Grand Teton peak. The sun was beginning its late afternoon arc over eastern Idaho, and the rock was golden with the soft rays. The sky above us was blue, and the prospect of a successful ascent had stiffened my resolve, though I was very tired.

After nearly six hours of continuous climbing, we reached the top. The valleys and the neighboring Teton peaks were spread out before us, with the lakes sparkling beneath the Douglas firs that provide scented gateways to this mountain range. It was hard to believe we were standing on the top of a mountain that's frequently enshrouded by clouds or mist. After congratulating one another, we signed our names on the piece of paper where successful ascents are recorded.

After that, Carman was anxious to get off the mountain. He understood the rigors of scrambling down to the base camp - a trip that takes two hours under normal conditions. But today's climb down was far from normal. The hail and snowstorm had left dangerous snow and ice on the route most climbers take down the mountain.

We made our way back, sliding down a 120-foot rope and picking our way down a seemingly endless trail of boulders to the base camp.

Our guide made his way to the tent to greet his next client, the retired electrician, Harry, who had returned from St. Louis for another climb up a Teton peak.

``Sorry I'm late,'' Carman said, extending his hand to tomorrow's client. ``Glad to see you.''

If you go

The basic course at Exum, required for all guided climbs of the Teton peaks, costs $41. Exum recommends you also attend the intermediate school, at $50. Exum's two-day climb up the Grand Teton starts at $165, which includes a guide and use of the base camp, sleeping bag, and cooking gear. You provide food. The hike to the base camp is about nine miles, with an altitude gain of about 5,000 feet.

To reserve a place in a class or on one of the climbs, write Exum (from June 11 to Sept. 11) at Box 56, Moose, WY 83012, or call (307) 733-2297. The school's winter address is 2627 Lombard St., San Francisco, CA 94123; telephone: (415) 922-0448.