Travels in Geology: Walking toward Whitney: A journey through the Sierra High Country along the John Muir Trail

by Kate Prengaman
Tuesday, February 18, 2014

From atop Mount Whitney — the tallest peak in the lower 48 states — ridge upon ridge of Central California’s Sierra Nevada range stretches out before you, the topography blurring into the northern horizon. My travel companion and I arrived at Mount Whitney’s peak after a 340-kilometer hike through the High Sierras along the John Muir Trail (JMT) — climbing up and down many of the ridges that now fade in the distance. Having just traversed the trail, one boot-step at a time, you can appreciate the scale of the scenery all the more: You’ll understand just how high you truly are and that those ridges, their severity now softened by distance, are anything but tame.

The trail is named for naturalist John Muir, whose writings on the Sierra Nevada championed wilderness conservation and helped birth the environmental movement in the late 19th century. A hike along the trail is a tour of the granite and glacial geology of the Sierra Nevada. The range was built by 2 million years of recent uplift, which followed millions of years of shifting plates and volcanic activity that built its foundation.

The hike to Mount Whitney traverses uninterrupted wilderness through three national parks — Sequoia, Kings Canyon and Yosemite — as well as national wilderness areas such as the Ansel Adams Wilderness and 13 different river drainages over which the ecosystems and geology continually shift. The trail brings you views of the imposing Ritter Range, the columnar-jointed basalt of Devils Postpile, red cinder cones and Yosemite’s iconic exfoliated domes. It’s not for the faint of heart (or the weak-kneed), but if you can make time for it, it’s a trip you’ll never forget.

A Steep Start

The traditional route along the JMT starts by heading straight up Mount Whitney and then continues northward toward Yosemite. But beginning at Yosemite and heading south, saving the tallest climbs for last, is considered easier and is the far more popular route today. In truth, there is no easy way to complete this traverse of the High Sierras. On our August 2013 trip, my friend Joanna and I opted for the latter route, hoping that finishing with Mount Whitney would offer a captivating climax for the trip and would ensure we’d be in better climbing shape by the time we reached the tallest passes.

The first climb out of Yosemite Valley, on the popular route to Nevada Falls and Half Dome, rises 610 vertical meters over 4.8 kilometers. We started from an alternate trailhead along the park’s Glacier Point Road, adding a few extra kilometers but saving ourselves some elevation gain — a worthwhile tradeoff in our estimation. Considering an alternate trailhead might make it easier to get permits for your first choice dates as well (see sidebar).

We jumped onto the true JMT at Nevada Falls. The waterfall is usually roaring as Sunset Creek drops about 180 meters, but last year was so dry that the creek simply slid quietly over the falls. This first part of the trail can be a bit crowded, and until you pass Half Dome, one of the park’s most iconic peaks, your heavy packs will look out of place among the lighter daypacks of short-term tourists. The present guise of Half Dome’s giant granite face was formed by exfoliation — the cracking and peeling of layers of granite unburdened by erosion as the peak was uplifted. This is dome country, the rounded peaks visible all around you from many viewpoints, but Half Dome dominates.

If you want to summit the peak, plan ahead and secure the necessary permits. Hauling yourself up the dome, using the bolted-in cable handrails that enable nontechnical climbers to scale the sheer face, is exhilarating, but the experience is daunting and not for those with acrophobia. Don’t even think about taking your heavy packs.

Beyond Half Dome, the JMT keeps climbing up to Sunrise Camp and Cathedral Pass. Just kilo¬≠meters from the day-hiking masses, there’s a surprising amount of solitude to be found in the ascent. Cathedral Lakes are the reward for your effort. They are just the first of dozens of shimmering alpine lakes that beckon you to camp near their shores, soak your sore feet in clear, cold water, and take photographs that never quite capture the true beauty of the steep peaks guarding them.

Shortly after exiting Yosemite to the south, the glacier-carved granite abruptly disappears, replaced by the darker volcanic Ritter Range, which stands imposingly above Thousand Island Lake. Much older than the surrounding granite formations, these craggy peaks are remnants of the ancient Minaret Caldera.

The trail descends and traverses through even older rocks — metamorphosed volcanic breccias, tuffs and colorful conglomerates whose beautiful and varied patterns and inclusions are enough to hold your attention for days, if you didn’t have to keep moving on toward your next food resupply.

A Wilderness Mindset

And so it continues, day after day. Break camp. Hike. Gawk at the scenery. Climb. Descend. Gawk again. Make camp. Cook. Eat. Stargaze. Sleep. Repeat. You develop a rhythm, but somehow, every day, the scenery gets better and better.

About a week in, you reach Devils Postpile, just outside Mammoth Lakes. The official JMT remains in the wilderness, skirting the national monument and the tourists, campground and lodge where you can resupply and buy an expensive shower. But most hikers take the brief detour, for the resupply or the geology or both. Devils Postpile is a formation of columnar jointed basalt that fractured into nearly perfect hexagonal columns about 100,000 years ago as a lava lake cooled and contracted. Erosion has taken its toll over time, with freeze-thaw cycles shattering some columns and others being toppled by earthquakes. The broken hexagonal bits form a talus slope below. As you return to the trail after your detour, you pass another unique volcanic spot, the Red Cones, and a trail covered in reddish-brown pumice, formed when the cinder cones erupted about 5,000 years ago.

Continuing on, you soon return to the more familiar glacier-carved granite landscape. Just over halfway through the trip, the trail climbs up to a hanging valley. A steep set of switchbacks then takes you to Evolution Basin, which features smooth granite slabs, deeply carved lakes that are home to the plump, endangered mountain yellow-legged frog, and tall, rough peaks, untouched by the glaciers, including Mount Mendel and Mount Darwin, named for the behemoths of genetics and evolutionary theory. The basin was scoured, and little soil has formed here.

Climbing past the lakes full of the fat frogs and up over Muir Pass, the geology again shifts dramatically into the black peaks of the Ionian Basin. You then skirt the massive metamorphic region known as the Goddard Terrane, which formed between 250 million and 150 million years ago when colliding continental plates kicked off a flurry of volcanic activity. Later tectonic movement metamorphosed the granite into the dark rocks seen today. 

The trail continues, up and down, up and down. There’s not much flat terrain on this trip, especially in the second half. The climb to each high pass has its own character, its own geology, and its own vast view of the landscape. The scenery is impressive, but so is the fact that this well-constructed trail is here at all.

Construction of the trail, named in honor of the man who introduced the country to the beauty of the Sierras and led the political push to designate areas of wilderness, began in 1915, the year after his death. Theodore Solomons, an explorer and naturalist a generation younger than Muir, dreamed up the crest trail as a teenager and spent years scouting out potential routes. The trail was finally finished in 1938 with the addition of the climb from the South Fork of the Kings River up to Mather Pass, a climb known as the Golden Staircase. The tight switchbacks rise 450 meters over a steep wall between the river valley and the Palisades Lakes below the barren talus. When hiking it today, especially when stopped on one of the dozens of switchbacks up the Golden Staircase, it is hard not to be in awe of the monumental effort that went into trail building, by workers with low-tech tools during an era when heavy equipment was pulled by mule teams.

After you crest Forester Pass, Mount Whitney begins to loom, with its broad, slanting peak dominating the ridge in the distance. It takes about two days from when you first see Mount Whitney to reach its base. Our last night on the trail we camped just below its hulking face near the last lake, which is shaped like, and named for, a guitar.

After hauling your packs up switchbacks that wind across the talus slope, you reach the highest pass on the journey, where you’ll be joined by surprisingly clean day hikers who have climbed up from the other side. You can leave your pack here and enjoy a few blissful kilometers of pack-free hiking as you trek along Mount Whitney’s ridgeline, winding past pinnacles and narrow windows that look down to the eastern desert valley below. Free of your pack, the 3.2-kilometer climb goes quickly. You finally arrive on the sloping, windswept peak, passing an emergency shelter to join the others posing for pictures and peering down in all directions. At 4,420 meters, you’re on top of the lower 48 states.

The descent is steep, quickly dropping from almost barren talus to alpine meadow to forest to high desert steppe in just a few hours. Strolling through the last kilometer of sagebrush makes it hard to believe that you were just on top of the world. You can savor the end of your journey slowly, or dash through, depending on how motivated you are to reach the shower, pizza and beer waiting for you in the town of Lone Pine at the end of your 340-kilometer journey exploring the Sierras.


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