THE forecast was promising: sunny and 80 degrees for days to come. Rock climbers Dan McOmber and Curt Chesney of Boulder, Colo., figured that with the arrival of June and good weather it was finally time to scramble up El Capitan, a mammoth rock face in California's Yosemite National Park that's a popular challenge for athletic adventurers.
But the weatherman was wrong. A fierce storm moved in, pelting the pair with rain and snow as they hung short of the summit. Water poured through their rain gear while howling wind drowned the sound of their voices. Mr. McOmber and Mr. Chesney clung to the wall for six of the coldest, wettest hours of their lives.
When the clouds broke briefly, a ranger spotted them. Weather prevented a rescue from below. Finally, a helicopter managed to land on the summit and haul the men up.
A happy ending? Yes - but an expensive one. At $15,000, the rescue's cost is a burden Yosemite can ill afford at a time US national parks can barely pay to pick up tourists' trash.
The McOmber and Chesney story is no longer uncommon. The number of thrill-seeking national park visitors - rock climbers, mountain bikers, river rafters, hang gliders, snowmobilers, and even helicopter riders - is rising fast. As it does, America's crown jewels of recreation are straining to handle the load.
Park fatalities are climbing, the number and cost of rescues are ballooning, and the remote park environment is eroding as never before. The National Park System is just now beginning to impose new regulations and fees to control the burst of activity.
''We're trying to educate and enlighten people to be more safety conscious and exercise caution,'' says Jim Lee, emergency service coordinator for the park service. ''There's no more funding to support search-and-rescue increases.''
The number of rescues in the national parks has jumped from some 3,000 in 1987 to close to 5,000 in 1993. Over the same period, the National Park Service reports a 10 percent increase in fatalities systemwide. Just since January, six mountain climbers have died and some two dozen more have been rescued in their attempts to reach the top of Alaska's Mt. McKinley, the nation's tallest peak.
The most costly rescues are those that take place in back-country wilderness, ''where people can over-estimate their abilities,'' Mr. Lee says, whether they involve snowmobilers, mountain bikers, or less intense sports enthusiast such as hikers.
''Invariably hikers win the prize for being unprepared for conditions,'' says Yosemite's acting search-and-rescue officer John Dill. ''A one-week search for them can cost between $100,000 and $200,000,'' he adds.
In fact, it is often novices and hikers, rather than extreme climbers or rafters - generally in better shape and more experienced - who tax the park system's rescue teams.
But rangers are not shy when grousing about the new, cavalier visitors they see in parks.
''People are much less self-reliant than when I started in the park 21 years ago,'' attests Jim Protto, chief of ranger operations at Rocky Mountain National Park in Estes Park, Colo. ''They don't think, 'I need to take care of myself;' rather, 'Who is going to come get me?' They used to carry a compass, map, and dress for the weather. The trend now is light is right, so it's just a fanny pack, water bottle, and cellular phone.''
Yosemite's Mr. Dill has witnessed the same phenomenon. ''I've been told rock climbers will be bolder at Yosemite, knowing there is a rescue team, than in some remote climb in Alaska,'' he says. ''This is wilderness, it's not a day-care center. People are supposed to be responsible for themselves.''
Despite the isolation of Alaska's mountains, the number of climbers is rising there as well, nearly doubling in the last 10 years. ''It's bizarre to walk into a camp at 14,000 feet and see two outhouses ... and 50 tents,'' says climber Nina Kemppel.
In the spotlight
But in Alaska's parks, the challenge is not only more extreme sports enthusiasts, but a boom in publicity hounds. Since June, two teenagers have broken records climbing Mt. McKinley in Denali National Park. A blind school teacher also climbed to the top, raising $90,000 for the American Foundation for the Blind and an awareness of the feats the blind can accomplish.
Park officials deride the ''circus atmosphere'' they say has descended on the mountain. ''This year it's 12-year-olds. Next year it's going to be 11-year-olds,'' says J.D. Swed, chief mountaineering ranger for Denali National Park.
To provide for the swarm of mountain climbers, the park service this year required a $150 fee for hiking up McKinley and nearby Mt. Foraker. The fees were the first climbing fees the park service has ever imposed.
And they're likely to be just the beginning. National Park Service safety officer Jim McCarthy says increased fees nationwide are ''in the works. They're not put there to restrict people from climbing,'' he says, ''but to offset some related costs, for instance to help maintain trails.''
The park service decided long ago not to charge for rescues, but as those costs rise, and Congress considers budget cuts, user and entrance fees may become a national park norm.
The damage that adventurists wreak on the plant and animal life in the nation's parks is often forgotten amid tales like that of a Spaniard who huddled on a wisp of a ledge waiting for help and eventually plummeted to his death this year in Alaska. But scaling mountains, climbing rocks, and exploring the underwater world can have serious environmental consequences. Activities such as mountain biking, snowmobiling, and helicopter touring can pester other park visitors.
''In Maho Bay, [Hawaii],'' says Paul Pritchard, president of the National Parks and Conservation Association, ''little of the spectacular coral is left. It's all been broken off, and the exotic fish have left the area.''
Near mountain biking trails, weeds and rodents have replaced the more rare and delicate plants and animals that most park visitors go to see.
Hikers inevitably leave trash, and as their numbers mushroom, their waste can pile up.
Chalks used by rock climbers can discolor the rock faces. And rangers are appalled at climbers who tear off a rock's vegetation to make their ascent easier.
The air up there
A new trend at the parks - air tours - is a danger to birds and a source of noise pollution for visitors. The tours, usually offered by private companies, allow participants to view nature from small planes and helicopters. But their popularity is causing air traffic jams, and the National Park Service is weighing how to further restrict the flights.
In 1987, the National Overflights Act was passed. It called for studies, restricted flights over Yosemite, and made planes below the canyon rim at Grand Canyon illegal. But the volume of small aircraft has soared. A recent study shows that from many points at the Grand Canyon, aircraft are audible 50 percent of the time.
Snowmobiling is also controversial. ''We've received hundreds of letters from our winter visitors concerned that the level of snowmobile use is inappropriate for the wilderness nature of this park,'' says Yellowstone Superintendent Mike Finely.
An average of 1,000 snowmobilers cruise around Yellowstone Park on a given winter day now. And the rest of a new 240-mile trail for snowmobilers is slated to open this winter (a portion opened last season), bringing thousands more snowmobilers into the park
How much damage?
Not knowing the true environmental impact of extreme sports is the biggest problem, Pritchard says. ''We have said for years, you cannot manage what you do not understand.''
In 1993, a call was sounded for officials to assess rock climbers' strain on the parks and suggest regulations.
From the federal registry: ''While rock climbing has been a long-accepted recreational activity in most park areas, because of the relatively low levels of use in many parks, there have never been regulations.... An explosive growth of rock climbing in recent years suggests that regulations and guidelines need to be developed....''
Two years later, national park restrictions on rock climbers are still not on the books. The park service is on the threshold of regulating adventure-seekers.
Measures applied to hikers in Denali - such as the new user fee, a proposed 60-day preregistration, and possible climber qualifications - are still controversial.
But even if climbing prerequisites are set, they won' t prevent all tragedies, Mr. Swed says. He points to three Washington State men who perished in a crevasse fall this summer. ''Those three guys didn't do anything wrong. It was just something that happens in the mountains.''