FOR two months of the summer, the head of Kahiltna Glacier - a 45-mile-long river of snow and ice 7,000 feet up North America's tallest peak - is the Grand Central Station of the Alaska Range. Climbers from around the world are drawn each May and June to 20,306-foot Mt. McKinley, also known by its Athabascan Indian name, Denali, which means ``The Great One.''
But now there are fears that the world's climbers might be loving The Great One to death. The problems of overcrowding - including waste disposal in a delicate environment - are prompting some to rethink McKinley's status as the world's last major mountain that doesn't require climbing permits.
The prospect of regulation chills Brian Okonek, a guide who first climbed the mountain 18 years ago. ``Mountaineering is such a free-spirit sport, and then when you start putting regulations on it, it just changes the nature of it,'' he says.
But the nature of the mountain is changing. Between 1985 and 1989 the number of climbers on McKinley grew from 533 to 1,009. This year's total, 718 climbers as of Sunday, appears to be keeping pace with last year's record, says Bob Seibert, chief mountaineering ranger for Denali National Park.
For almost all the climbers, Kahiltna Glacier is the first stop in this world of rocky spires, snowfields, blue glacial ice and - new this year - brown-gray ash courtesy of Redoubt volcano, 200 miles to the southwest.
About 50 people and their campsites were clustered last Saturday on the glacier that is part natural wonder, part moonscape and part air base. Colorful domed tents hugged the smoothed-out surface that serves as the airstrip for glacier pilots who landed and departed every 20 to 30 minutes during the day.
The crowded conditions continue further up the mountain. Some 80 percent of McKinley's climbers use the West Buttress route, the quickest, least technical route up to the summit. That makes for crowds at narrow spots, tensions between faster and slower climbers, and, in some areas, traffic jams.
One of the most serious problems is the way climbers answer the call of nature. Near the snow runway is an open-air latrine. At the camp on the 14,200-foot level, is another. Elsewhere on the mountain, climbers are supposed to dispose of their bodily wastes down deep crevasses.
Setting up and maintaining outhouses all along the West Buttress route would be too expensive for the National Park Service, which has a $5 million budget for all of 5.9 million-acre Denali National Park, says John Quinley, the agency's Anchorage spokesman. Park areas other than the mountain receive many more visitors - perhaps 1,000 for a summer Saturday on the park's road entrance - so that is where most of the money is spent, he says.
Climbers say most of their comrades follow the Park Service's sanitation rules, but there are violators who alienate the climbers following in their wake.
The rules also require McKinley climbers to pack out all their garbage. Even when the rangers are absent, the mountain's climbers keep eagle eyes out for other climbers' trash, a serious problem on peaks such as Mt. Everest.
So far, the vigilance appears to have paid off. Mountain veterans say climbers have become increasingly conscientious about packing out their trash, and that McKinley is freer of nonbiodegradable junk than it was 10 years ago.
But the very nature of mountains invites trash trouble, experts say. Climbers overcome by altitude sickness or exhaustion often lack the energy to clean up after themselves. And a lapse of attention can allow trash to blow away.
Concerned Park Service officials this season began formally surveying mountaineers for solutions to the crowding dilemma.
Should the National Park Service mandate a permit system for McKinley?
Tom Downey and Greg Aramaki, climbers from Seattle, say yes. The tanned climbers say the crowds detracted from the expedition into which they had invested over a year of planning and practice and thousands of dollars. ``For me, it was just too much,'' Mr. Aramaki says. ``It's a traffic jam.''
Mr. Seibert is hoping to avoid measures that would compromise McKinley's free atmosphere. ``In most other countries, you have climbing fees and permits and a great deal of rigamarole, but that has nothing to do with protecting the environment. Most of the major mountains in the world have significant bureaucracies attached to them,'' he says.
Should climbers be encouraged to schedule expeditions outside of the May-June seasonal crush?
Perhaps, experts say, but there are associated risks. April is often too cold for most climbers, and July can be too snowy and wet.
Should climbers be steered away from the West Buttress?
The one alternative route that is not more technical than the three-week West Buttress route demands four weeks to complete, and that adds its own challenges. Other routes are even more demanding. Nonetheless, more climbers are opting for alternate routes, Seibert says.
Tom Kelley, a Golden, Colo., civil engineer who returned Saturday from an unsuccessful attempt on the West Rib, says his move was inspired by irritation with the West Buttress crowds. ``It's a neat route, but it's just such a zoo,'' he says.
Few McKinley longtimers claim to know the solution to the mountain's ills.
As he packed food last week for his second guided trip up the mountain this summer, Mr. Okonek wore a T-shirt that read ``Never Trust Anybody Under 20,320 Feet'' - McKinley's official elevation until its height was remeasured last year. He hopes those who love the mountain can be trusted to protect it from overuse and pollution.
``I've just kind of shoved it aside and hoped it would regulate itself,'' he says. ``It's hard to believe you can take such a beautiful place and even have this as a subject.''