For those who haven’t been to Yosemite Valley, any words I’d use to describe it – beautiful, majestic, stunning, awe-inspiring – would seem to be overkill. For those who, like me, have seen and loved this place, those same words wouldn’t be nearly enough to do it justice. Yosemite is, without a doubt, one of the most beautiful places I have ever been. It is vibrant, with green trees, gray rocks, blue lakes, and white foamy waterfalls. It has the ability to make you feel small, dwarfed by the pinnacles above and around. And around each bend is another stunning surprise. It is, truly, like nowhere else.
But how did such a wonder come to be? And how can one experience that creation today? This is a story of water, rock, and ice.
Tens of millions of years ago, the granite that would become California’s Sierra Nevada mountain range burst through the Earth’s surface along a fault line, pushed upwards from its creational point by the forces of plate movement. The granite isn’t monolithic, but was created over hundreds of millions of years, thereby leaving it subject to intrusions by magma, which left softer patches. As the domes and spires of what would become Yosemite Valley’s walls pushed upward, newly formed rivers like the Tuolumne and Merced found their way down through these softer spots, carving the beginnings of canyons and valleys between the harder granite.
Two or three million years ago, the world cooled drastically, and glaciers formed in the higher elevations of what was now the Sierra Nevada range. As they flowed downward, they adopted the paths of least resistance: the river paths that had already been established. When the glaciers retreated at the end of that ice age, their presence left the valleys, like Yosemite Valley, widened, with semi-circular features unique to glacial valleys. Boulders carried by the glacial flows were left scattered in these valleys, and the rock walls were smoothed.
Yosemite Valley would continue to change – changes that go on to this day. While granite is an incredibly hard rock, hardly subject to natural wind or water erosion, it forms with natural cracks. Rainwater – or water from the many streams and rivers of the area – gets into those cracks. When it freezes, it expands as ice, widening the cracks. Over time, soil finds its way into wider crevices, and plant life grows. Between ice and plants, the cracks widen even more, and eventually get so big that huge faces break off from the granite walls. (Most recently, a rock fall in 1996 near Happy Isles brought 68,000 tons of granite down a nearly 2000 foot vertical drop. The subsequent shockwave and dust wave felled trees in a large area, killing a hiker and severely wounding two employees. In the 80s, a rock fall more than twenty times that size broke off El Capitan, and an estimated fall twenty times that was what probably dammed Tenaya Creek, leading to the creation of Mirror Lake.)
The result of all of this is Yosemite Valley, about seven miles long, a mile at its widest point, and sitting 3-4000 feet below the granite walls around. The Merced River still flows through the middle of the valley, dropping rapidly during the course of its travels, with the twin falls of Vernal and Nevada (accessible via the stunning Mist Trail) being the largest drops. Smaller rapids and cascades near Happy Isles also illustrate the downward flow of the river. Other creeks and streams flow into the Merced River, but with the granite being too hard to easily carve into canyons, the result can be spectacular waterfalls dropping hundreds of feet down the cliff faces. The two largest and most easily experienced of these are Bridalveil, which falls 617 feet (it is the waterfall on the right from the iconic Tunnel View) and the stunning Yosemite Falls, which over the course of the Upper and Lower waterfalls descends 2425 feet. The upper falls are so tall that the water descends more as mist than a constant rush of water.
(On this trip to Yosemite, I hiked the Upper Yosemite Falls trail, although not all the way up because I’m not in shape for that. Over about 2 miles from the base to just past Columbia Rock, the trail ascends over 1000 feet via a ton of switchbacks, but the reward is the most amazing view of the falls I’ve ever seen.)
For a bird’s eye view of Yosemite Valley, drive to Glacier Point. (The road is closed in 2022, but will reopen next year.) From here, one can see Yosemite Falls, the Merced River as it tumbled over Vernal and Nevada Falls, and the two most iconic rock formations in the park: El Capitan and Half Dome. It is believed that Half Dome was created by the most massive rock fall the valley would have ever seen, and then smoothed by glacial ice, although nobody knows for sure.
You can contrast Half Dome with the complete Sentinel Dome – best seen from Happy Isles – to get an idea of what it might have originally looked like. Domes like this are a naturally occurring shape of granite as it pushes upward.
Tens of millions of years of geological history have gone into the creation of Yosemite Valley, a place that could only be more perfect if the crowds stayed away and left it for me alone. It is the crown jewel of the National Parks Service, one of the most beautiful places on Earth, and a place I am happy to visit as often as possible.
This is not the first article I’ve written about Yosemite. Click here for an overview of the park, and click here for an in-depth look into the parts of the park south of the valley.
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