ApproachThe traverse between Tresidder's north and south summits begins on the lower north summit of the peak.
From the Cathedral Lakes trailhead in Tuolumne Meadows, follow the John Muir Trail (JMT) to just past the uppermost of the Cathedral Lakes. Leave the trail here and hike southwest through the forest and up low-angle slabs to the base of the peak's north arete. An easy scramble up a crack/slab/block system (class 3) leads to a small notch between the north summit block and a lower block to its west. The summit block is climbed by a short mantel.
Route DescriptionThe route is fairly obvious from this point--with only two or three exceptions (detailed below), one follows the crest of the knife-edge ridge fairly religiously to the higher south summit. This is a short traverse (only about 200 yards as the crow flies), but it's sustained and exposed class 4 (and some low 5) for almost the entire length. (Even climbing unroped, the traverse took us the best part of an hour). The rock is generally fairly sound along the ridge, but caution must be exercised when weighting some of the abundant chickenheads encountered along the way.
The first obstacle encountered along the ridge is the downclimb from the north summit. The south side of the summit block is a steep wall, which can be bypassed by downclimbing a low fifth class ramp/crack on the right (west) side of the ridge. This leads down to a small notch along the ridge.
Gain the ridge again, and follow it to the second obstacle--a descent of another short, steep wall, which is again bypassed by a short fourth class downclimb and traverse on chickenheads on the right (west) side of the ridge, leading to another small notch.
Back on the ridge again, follow the thrilling knife-edge to the final obstacle, a short, steep crack and overhanging roof that lead up to the south summit. This is probably about 5.6 or so; as of September, 2005 there were a couple of old rappel slings here to make it look more intimidating. This can be bypassed by downclimbing a class 4-5 ledge system on the left (east) side of the ridge, then climbing an easy 5th class ramp that leads up to the east side of the summit block. The summit block is an easy scramble from here.
Descend the south arete by heading down the left (east) side of the arete from the summit block. Downclimb a crack and open book to easy ground. One can continue south to Columbia Finger, or head east down easy slabs to the JMT.