Isosceles Peak CS

Aug 8, 2019

With: Sean Casserly
Scott Barnes
Iris Ma
Tom Grundy
Rob Houghton
Clement Guillaume
Chris Henry
Grant Miller
Zach Moon
Asaka Takahashi
Sean Crom

Etymology Story Photos / Slideshow Maps: 1 2 GPX Profile
previously attempted Aug 10, 2005


I had first been to Isosceles Peak during the 2005 Sierra Challenge, surprised to find that the final ascent to the summit block was class 5 and outside our scrambling abilities. I had given everyone who'd gotten to the lower east summit credit for this one, then mostly forgot about it for the next decade. Jonathan Mason goaded me in 2018 for listing it as an ascent on PB and LoJ, even though I had not been to the summit. It was fair criticism to which I modified the entries, then concluded to put it on the Challenge again, now 14yrs later. The main concern was similar to that we faced for Kearsarge Pinnacle #8 the previous year - how to get a dozen folks safely up and down a roped climb. There had been some feedback from Kearsarge Pinnacle #8 that the effort had been a little haphazard and unsafe, again fair criticism. In consultation with Tom Grundy, I assigned him the task of being our climbing manager, the point person for choosing the route, style and gear for the climb. We would have other strong climbers as well, including Zach, Iris, Scott and Grant, so I figured we'd have plenty of expertise - it just needed to be coordinated. We brought three ropes and plenty of gear, distributing it mostly to the fastest group as a handicap, but everyone had their own rock shoes, helmet and harness. We had 16 for the 6a start at the Bishop Pass TH, though only a dozen of those were heading to Isosceles.

The hike up to Bishop Pass has been done more than ten times over the course of the Sierra Challenge, a well-worn route described in much detail on those earlier jaunts. Because we'd have to reassemble the group for the roped section, there was no real advantage to speeding ahead, so the group did not splinter quite as rapidly as usual. I found it just as beautiful as ever, past Mt. Hurd, Long Lake and other familiar landmarks. Just below Bishop Pass I paused with Rob to examine the deer bone pile, now two years since that fateful fall day when almost 50 deer slid to their demise down an icy stretch on the north side of the pass. The stench has lessened, but there are still flies finding reason to hang around. We went over the pass around 7:45a before dropping into Dusy Basin and making our way towards Isosceles, easily visible from the pass. I went with Rob and a few others around the north and east side of the largest lake in the basin, while others went around the west and south sides. From a distance the northeast slopes leading up to Isosceles look steep and cliff-ridden, a concern that Rob voiced to me on several occasions as we crossed the basin. I assured him that there's a class 3 way up which would become more apparent as we got closer, but to be honest I had to agree that it looked difficult - I had little memory of it from 14yrs ago, only that it wasn't terribly memorable.

From the edge of the lake, we started up the slope, initially on low-angle snow that went fairly quickly. Where it began to steepen appreciably, we moved onto the rocks and boulders since we'd brought no crampons or axes with us. There was only one short section of snow above this to cross, which we did carefully. We weaved through cliff sections as required, keeping the scrambling to class 3 or easier, as promised. As we topped out on the East Ridge, we found ourselves with more company. Zach had caught us from below, while Chris, Sean Casserly and Asaka, having started earlier, were just ahead of us. The ridge starts as class 2 but becomes class 3 with a few stiff sections requiring careful attention. In particular was a 15-foot wall with fair holds that made folks cautious. Clement had beaten everyone to the top, posing grandly atop the east summit, watching us from above. By 10a we had most everyone at the east summit while Tom and a few others began surveying the more difficult route to the highpoint on the middle summit.

There is a notch between the east and middle summits with an arch that can be seen from below if one knows where to look. Downclimbing to this notch is class 3-4, an open book with good holds. Not everyone was comfortable doing this, so a line was fixed from above to allow folks to rap down it as an option. From the notch, one can climb up on the south or north side of the ridge. Tom and a few others were eyeing the southside option which had been used by Eric Su, Sean Reedy and companions the previous year. I thought the northside option shorter and on better rock, and it was this 25-foot route that was settled on. With Tom managing the climbing part, most of us waited back at the east summit while Grant led the climb, belayed by Tom. It had been an hour since we'd first reached the summit, and we found it was almost 11a before Grant finished the short pitch, though it took him only about five minutes, placing one cam for protection. He set up a belay station at the top of the class 5.7 short pitch, then brought Tom up, the latter climbing the last short distance to the summit block, class 3-4. Tom then returned back to the notch, Grant staying at the belay ledge, and the pair were soon ready to ferry the rest of us up and down. Zach had not liked the looks of clouds forming overhead and decided to head back with Sean Crom. It took about two hours to get everyone up and down, not in any strict order. Some of us scrambled up and down the upper section to the summit block, others rapped down to the belay station on a short rope. All of us would rap the steep crux. At most, we had seven of us at the summit at one time. The register we found was held in a plastic container whose lid had broken. The contents had been shredded, probably by small rodents who make their home here. We left a new register in its place. Grant, who had been a great sport in belaying everyone up the crux section, was the last to stand on the summit block. We eventually got everyone back over to the east summit, collected and packed up all the gear, and were ready to head back by 1:30p. The clouds overhead had gotten no worse than when we'd arrived hours earlier, mostly just rearranging themselves in the sky.

After reversing the route back across the East Ridge, some in our party headed off to nearby Columbine Peak while others, including myself, descended the north side back to the lake in order to return over Bishop Pass. Tom and Iris paused for a swim at the lake while Rob and I continued back, content to stay dry and perhaps a little sweaty. It was 3p before we went back over the pass, meeting up with Zach on the north side, having taken his time on the return to concentrate on his photography. Rob went off jogging down the remaining trail while I continued my walk. Scott and Iris would catch up with me, only to fall behind while Scott went up to Chocolate Peak (perhaps the most popular bonus peak during the Sierra Challenge, ever) and Iris went for a swim. It was 5p by the time I got back, not really as tired as the late finish would suggest - sure makes for an easy day when you get to sit around for four hours in the middle of it...


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