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Tenaya Creek is a relatively minor tributary of the Merced River, but Tenaya Canyon is nearly as deep as the Grand Canyon. That would seem to be a bit of a mystery, since the size of glaciers in a canyon can be roughly comparable to the size of the watershed, and it looks like there was a very large glacier here. Studies of the glacial topography help to explain the disparity: large masses of glacier ice spilled over the divides from the Tuolumne River drainage, adding to the ice load in Tenaya Canyon. As big as they were, glaciers never overrode the summit of Half Dome, which looms thousands of feet above the lake. They instead undercut part of the base of the dome, taking advantage of joint patterns in the granitic rock to quarry rock away from the 700 foot-high face.
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Lest one thinks that the rockfalls in Yosemite are a thing of the past, a large rockfall occurred here just a few years ago (see some posts on the Ahwiyah Point fall here and here). Ahwiyah Point is the prominent summit just east of Half Dome (below). The rockfall destroyed hundreds of trees, and a hiking trail, which is still closed to entry due to continuing danger from falling rocks.
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4 comments:
Loving this series on Yosemite. One question I have is about other Sierra Yosemites. Where are they? I know Hetch Hetchy, but where are the other similar valleys (aside from "little Yosemite" in Sunol Regional Park)? Done a fair amount of Sierra backpacking but have yet to see something similar.
Not to belabor the point, but I reread my Muir and he notes, "several other yosemites have been discovered in the Sierra that occupy the same relative positions on the Range and were formed by the same forces in the same kind of granite." I can think of places, such as the Merced River Canyon near Triple Peak Fork, with high granite walls, but can't think of valleys aside from Hetch Hetchy similar to Yosemite. Much appreciate any answers, especially since I am getting my summer backpacking itinerary together now.
Hi KC, thanks for the comments! There is really no place quite like Yosemite, but Kings Canyon comes to mind, with several towering cliffs and a downstream section more than 7,000 feet deep. The North Fork of the Kings has the Tehipite Valley, with 3,000 foot Tehipite Dome (I haven't been there yet, pretty isolated). Tokopah Valley in Sequoia has some nice cliffs. Kern River Canyon is deep and straight, but I haven't seen it up close either (looked down in while approaching Whitney many years ago. The only other place that comes to mind is the Balloon Dome area on the San Joaquin River.
Garry, thanks for the locations. I've heard about the other Yosemites all my life (figured Kings Canyon would be one of them), but have yet to see a list. Since I've done a fair number of trips in the northern Sierras, it makes sense to me that south of Yosemite is where the other Yosemites are. That being said, there are some pretty amazing places up here, including the area around Noble Canyon near Ebbetts Pass, that may not be in the list, but almost as beautiful both geologically and aesthetically.
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