A kamikaze descent with a mountain bike down the switchbacks off Mammoth Mountain's 11,053-foot summit in the High Sierra. . . .
Combining wilderness horsepacking in the Wallowa Mountains of Oregon with white-water rafting on the Deschutes River. . . .
Backpacking across the 10,000-foot Beartooth Mountain plateaus, granite peaks and glaciers of Montana. . . .
Discovering little-known white-water adventures in Michigan and the Poconos of Pennsylvania. . . .
Riding nature's roller coaster in Alberta, and diving among the submarine peaks in Mexico's Sea of Cortez. . . .
From coast to coast, from the Canadian and Mexican borders and beyond, adventure vacation travels are offered this summer to suit every mood and interest.
These adventures can be both harrowing or part of the swiftly growing "soft adventure" market.
But let's start with the spine-tinglers.
Mammoth's New Kamikaze
My wife and I first went to Mammoth Mountain, in California's eastern Sierra, when Dave McCoy opened it in 1944 with one rope tow. Now the world-famed ski resort has become a vacation destination for every season.
You can check out the latest attractions for the active traveler through the Adventure Connection, headquartered at Mammoth Mountain Inn at the base of the main ski area.
Summer adventures are highlighted by mountain biking, which has been called the fastest growing sport in America. Two- and three-night biking/lodging packages feature a gondola lift with your bike to the 11,053-foot summit of Mammoth Mountain.
From there the thrilling kamikaze descent rolls down steep switchbacks, cliffside corners, radical downhills and wide-open straightaways. The two-night package at $150 per person, double occupancy, includes breakfasts, mountain bikes and helmets, a self-guide map of mountain trails and the guided kamikaze descent. Call toll-free (800) 228-4947.
Above the alpine lakes in northeastern Oregon, the Wallowa Mountains rise to 10,000-foot peaks. Three days of horse-packing among the wildlife of this seldom-seen wilderness, and two nights of camping are part of a seven-day, six-night package offered by Portland-based Personalized! Outdoor Adventures.
You meet your pack horses and guide at Wallowa Lake after driving old pioneer routes beneath the waterfalls of the Columbia River and through Nez Perce Indian lands.
The horse-packing is followed by two action-filled days of white-water rafting down the Deschutes River, as French fur trappers of the 19th Century so aptly named what became "The Chutes" to English-speaking pioneers.
From there you are on four wheels again over the snow-capped Cascade Mountains back to Portland. Tour dates this year are June 18 and Aug. 6 and 27. Price per person is $988. For more details and reservations, call Personalized! Adventure Tours at (800) 248-0414.
The Sierra Club again offers outings throughout the United States and in many nations around the globe.
The July 23 to Aug. 1 backpacking adventure in Montana's Absaroka-Beartooth Wilderness is recommended for "well-seasoned, well-conditioned backpackers who want to experience one of America's premier alpine wilderness areas."
It begins with a trek across the 10,000-foot Beartooth Plateau, descends East Rosebud Canyon, then climbs to Sundance Pass. The trail days are alternated with camping days to scale challenging peaks and observe wildlife. All trip members help carry food and commissary gear in addition to personal belongings, and share cooking and cleanup chores.
Michigan White Water
The cost is $435 per person for the club's nearly 500,000 members. Adult non-members add $33 for a year's membership, students and seniors add $15. For details and the complete list of 1989 adventures, rated from easy to strenuous, contact Sierra Club Outings, 730 Polk St., San Francisco 94109, (415) 398-5384.
The initial prospect of finding highly challenging white-water paddling in Michigan came as a surprise. A canoeing magazine described the western Upper Peninsula as "offering the most challenging, interesting and little-known white-water paddling in the Midwest."
The Piers Gorge stretch of the Menominee River near Iron Mountain was described as Mid-America's "fiercest piece of running water." We've canoed the peninsula and wondered how we could have missed so much nearby white water during our student days in Wisconsin.
This summer Michigan will have more than 100 canoe rental and supply bases. Organizers stress that all you need to take is "the will to ride or tame a river." Free canoe lessons are being offered, and there are combination packages with bed and breakfast inns.
For details and a Start Your Summer Now brochure, contact the Michigan Travel Bureau, P.O. Box 30226, Lansing, Mich. 48909, (800) 722-8191.
Only two hours from either New York City or Philadelphia, Lehigh River Gorge State Park in the Pocono Mountains of northeastern Pennsylvania is becoming one of the most popular white-water rivers in America. You can take it mild or take it wild.