Thompson Peak (Trinity Alps)

6-8 Aug 2004 - by Rob Yang

This was a 3-day solo backpacking trip to visit the north fork Trinity river area of the Trinity Alps Wilderness, especially Grizzly Lake (7100') and of course Thompson Peak (9002', highest point in the wilderness). I'd wanted to visit this area for a couple of years, but hadn't thought to ascend the peak until recently.

Day 1: Hiked in from Hobo Gulch about 17 miles / 2600'. Admired the river and its many pools, stopped and looked at the Jorstad cabin, and enjoyed the waterfalls and wildflowers further up Grizzly Creek. Trail was quite level and gentle, paralleling the river for the first 10 miles or so under heavy tree cover, then started to climb in earnest. The weather was mostly-cloudy, which cooled the otherwise hot August temps in this low-elevation locale. Camped around 5600' in the forest below Grizzly Meadows. Thompson Peak had clouds about it, and looked foreboding from the trail.

Day 2: Weather cleared. On my hike up I was surprised to see small snowfields at the head of Grizzly Meadows, where the falls came crashing 800' down from the lake, seemingly out of the sky. Made it up to the lake by 9, though the forest service scramble trail was a little confusing. Grizzly Lake was as beautiful as it was described. Words just don't do it justice. Camping up there is apparently not encouraged, to avoid impacting the fragile alpine environment, but that didn't seem to stop a lot of folks.

The 'permanent snowfields' or 'mini-glaciers' I'd been warned about were definitely present, but not an obstruction to the route I wanted to take: up to the low point on the ridge from the north shore of the lake, traversing above the an obvious gully, then the backside of the ridge to the peak. I'd actually packed in an ice axe and crampons all this way, only to stash them in some bushes.

It was maybe class 2 up to the ridge (made it by 10), mostly just a steep x/c hike. A use trail was evident in places, but filled in with slippery scree, making the granite blocks much more pleasant. The ridgetop had a couple of nice flat spots for a picnic / rest / etc. where a use trail continued on, then petered out. Eventually I decided to just scramble the boulders atop the ridge, which led me to the summit, where a bit of short class 3 maneuvering was required.

There were a couple of different blocks to choose from:

  1. the summit register, plus two USGS markers (took me until 11:15),
  2. ) the true summit block, which maybe was foot or so about the summit register and had two more markers,
  3. a somewhat lower block with a memorial plaque affixed. Being a climbing-school dropout I bailed on sitting atop the true summit block (which may actually have been class 4), but did manage to get a hand up. Does that count ? It was an interesting exercise, in any case.

Views were fantastic : Caesar Cap Peak and Shasta to the east, Mt. Hilton and the Canyon Creek lakes to the south, and the deep blue of Grizzly Lake to the north. I was amazed to see little crevasse-like creases in the perma-snow below the peak.

Descended back to the lake by 1:45 or so, where the sun was warming things up, but by the time I got back down to the trees a nice breeze started blowing after a few benign clouds gathered.

Day 3: Got an early start and packed out the way I'd come, hoping to beat the heat at lower elevations. Took note of the many varieties of trees, and the similarity of the lower elevation part of the trail to other coastal areas (madrone, mixed oak/douglas fir). By noon I was back at the car.

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