OverviewThis route rises from remote and seldom visited "Sky High Lake" to the equally remote and unique Sierra Crest alpine garden of the Keyhole Plateau. Little about this route will appeal to the peakbagger on foot, but for the ski mountaineer, it can't be beat. It's a large, open, uniform slope with consistent snow coverage, spectacular location and a somewhat obscure summit. The Keyhole Plateau, along with neighboring Mts. Darwin, Lamarck and Thompson are unique in their flat summits basically right on the Sierra Crest.
Getting ThereApproach one of two different ways:
-Via Paiute Pass and the North Slope of the Keyhole Plateau. This option gives you an excellent one-day, loop tour from North Lake, or even Aspendell in Mid-winter (when 168 is still snow-covered). You would climb the aforementioned route and descend the SE Slope, reversing the approach detailed next.
-Via Grass Lake, Lamarck Lakes and Sky High Lake. As mentioned above, this route holds little appeal to the summer mountaineer, and the following description is for winter travelers. From North Lake, find the bridge over the creek, near where the road forks to the Pack Station and the Campground, respectively. Don't cross the bridge. Instead, work your way up along the south shore of the creek draining Grass Lake. Once at Grass Lake, sort out the drainages above: Leftmost is the winter/snowy "drainage" approach to Lamarck Col. The next drainage to the right comes from Lower Lamarck Lake. Snow coverage varies, leaving the exact route to your discretion. From lower Lamarck Lake, ascend to Upper Lamarck Lake, across this and up the drainage to Sky High Lake.