Mount Rainier is perhaps the single most impressive mountain in the 48 contiguous United States. It ranks fifth in height, a tiny bit lower than California's Mt. Whitney (14,494'/4418m) and three Sawatch Range peaks in Colorado. And it ranks second to Mount Shasta in total volume for a single peak. But no other peak has the combination of high elevation, massive bulk, and extensive glaciation--and Mt. Rainier stands alone in splendid isolation, with only 40 miles separating sea level at Puget Sound from its glacier-clad summit. No other peak nearby even remotely challenges its supremacy.
In most of the United States, a hike of 3000 vertical feet to the summit of a peak is considered about average; 4000 to 5000 vertical feet is considered a very long and extremely tiring trip, and anything above 6000 vertical feet is rare and devastatingly difficult. However, Mt. Rainier, by its easiet route, requires ascending 9000 vertical feet (that's 2740m for you non-Americans). This distance is the same as for the climb from advance basecamp in the Western Cwm to the summit of Mt. Everest.
Even though Rainier's elevation is low by the standards of the Himalaya and the Andes, there are only 20 mountains on earth have more topographic prominence--it just beats out K2 for spot #21 on the list of most prominence peaks on earth. Mount Whitney, at #81, is the next peak in the contiguous USA on that list.
Mt. Rainier can be seen from 150 miles away, and makes an appropriate design for Washington's license plate, since it's visible from such a large chunk of the state. Looming over Seattle and Tacoma, sometimes above the layer of clouds, Rainier has an overwhelming presence like that of few other peaks in the world.
The upper mountain is covered with large glaciers and snowfields covering over 30 square miles, much of this terrain covered with yawning crevasses.
To the casual tourist or climber, the only current evidence of volcanic activity on the mountain is some ice caves in the small, shallow summit crater, created by steam melting the snow. However, geologists consider Rainier an active volcano, and small eruptions were seen in in 1894-1895. As recently as the year 1400 a devastating lahar from the slopes of the mountain inundated large areas of lowland with thick mud deposits.
As of 2007, the National Park Service allows three professional guide services to conduct clients to the summit of the peak and to offer mountaineering programs on its slopes. A three-day trip generally costs about $800 to $1100 and includes a day of training, a day to hike halfway up the peak, and a long third day when you summit and return to base. See the "Other Web Sites" section above for information from these three companies.
Any well-coordinated and experienced hiker in excellent physical shape can make the climb with the guide services. The biggest variable is the weather--if the date of your scheduled climb is stormy, you might not even make it past the halfway camps of Camp Muir or Camp Schurman (but they still take all your money). Also, be aware that many guided climbs end at the crater rim, a short trip from the true summit at Columbia Crest.
It is certainly possible for very fit and experienced mountaineers to climb the mountain without a guide. You do have to register with the National Park rangers and pay a small fee, but beyond the sheer scale of the peak the easier routes don't present much of a challenge to those used to crossing glaciers. The Camp Muir-Disappointment Cleaver route is usually a wide, trenched-out path made by hundreds of climbers every day, including the 30-strong RMI guided group.
Other routes offer more solitude and/or challenge. The Interglacier-Emmons Glacier route is the second most-used, and avoids the crumbly rock of the Disappointment Cleaver for an endless glacier trudge. The Liberty Ridge on the northwest is perhaps the most famous of the more difficult routes, which vary all the way to the nearly-impossible Willis Wall, a 4000-foot north face of crumbling rock and ice.
A few tips for those considering doing the Camp Muir-Disappointment Cleaver route without a guide:
1. Be in excellent physical condition. I've heard that climbing Rainier is like running a marathon, so a training regimen beforehand is a good idea. Recent (within the past week) high-altitude expeience, such as time spent scrambling in Colorado, is a help, too.
2. Wait for good weather. Storms on this mountain can be horrible, but summer usually sees several good, long stretches of sunny, cloudless, and settled weather. Not having strict time constraints and waiting for one of
these periods is a good idea.
3. Water, water, and water. Drink lots of it. Plan to spend several hours at Camp Muir melting snow, and leaving for the summit with a gallon per person is not unreasonable at all.
4. Leave early--both from Paradise on the first day, so you can get your camp set up, melt snow, and acclimatize in the afternoon--and from Camp Muir. RMI starts out at about 1 AM, and leaving at midnight is pretty common. Fresh lithium batteries in the headlamp help keep a good beam for the hours of hiking up in the predawn chill.
5. Early season (through mid-July) is usually better than later, since by August the crevasses have opened up into yawning chasms that often take lots of time to circumvent.
6. Know how to do pulley systems for crevasse rescue. Crevasse falls along the heavily used routes are rare, and there are usually lots of people around to help pull someone out, but you shouldn't count on that. Buy a good book on the subject and practice it as much as possible.
7. A party size of three or four is best. Two-person crevasse rescue can be dicey, and solo climbing is reckless and heavily frowned upon by the park service.