Mt Thompson is one of the highest summits of the Coast Ranges in California. Although eclipsed by the higher Mt Eddy to its East, Mt Thompson is an outstanding peak and an infrequently climbed challenge. While in the region on my road trip, I settled on an overnight climb using the China Gulch, Grizzly Lake and West-Northwest Ridge. The climb is mostly a long hike but glacier/permanent snow fields and a class II/III at the top add to the challenge.
In spite of Mt Thompson's prominence, I didn't find the best information online so I'm writing a more detailed trip report in hopes of guiding others.
Getting to Mt Thompson's China Gulch Trailhead
Of the little available information online, China Gulch looked like the best, most established trailhead for Mt Thompson. I followed decent directions from Summitpost but I'll provide my assessment as well. Coming from the East and I-5, I exited at Yreka and drove Highway3/Fort Jones Road through Scott Valley and the small town of Etna. I had cell reception most of the way.
At the town of Callahan, I took Callahan-Cecilville Road West to the town of Cecilville. This is a paved, well-maintained road but I doubt its regularly plowed in the winter. This winding and very steep road ascends to the crossing off the Pacific Crest Trail near Russian Peak, then descends just as sharply into the map-dot of Cecilville. There's no cell reception after leaving Etna. Cecilville itself has a gas station and market but I recommend filling up well before then, just in case.
Approximately 2.2 miles before arriving in Cecilville, there's a paved road departing the highway on the left which crosses the South Fork of the Salmon River. I took this road, known as Caribou Rd/Forest Rte 37N24 South. At 2.4 miles after departing the highway, I arrived at the Forest Service station (closed due to COVID19). Given the remoteness, I doubt they regularly staff the station.
Driving a further 1.2 miles on this road, I came to the end of the pavement and fork in the road. I headed right up this road, marked as FR 37N07. From here, I generally just followed the most well-traveled dirt road 5.9 miles to the China Gulch Trailhead which was marked and had plenty of parking. There were a few forks in the road along the way but none confused me.
I had no trouble passing the road in a Subaru Outback. Most passenger cars won't have trouble either.
Here's my overall map which includes the driving approach and the entire route I took up Mt Thompson:
Section 1: Trailhead to Rays Peak Pass, down to Hobo Gulch Intersection
China Gulch is the closest trailhead to Mt Thompson but it comes at a price; a 1,000' up-and-down which brings you no higher up the summit. Starting at the trailhead, I made the arduous, initial climb to Rays Peak Pass (altitue ~5,800'). The initial altitude of the start is 4,800 and I gained 1,000' over 1.9 miles. At first the trail winds through a wildfire scared area which has nice views to the West but is rather scortched otherwise. A few water sources trickled across the trail.
Once I gained the "summit" of Rays Peak Pass, Mt Thompson came into view. The tooth-like summit with its corresponding glaciers loomed far off in the horizon, reminding me of a long day ahead.
Descending from here, the trail enters into a not-burned forest, past China Spring and down a few switchbacks to the Hobo Gulch junction. This is the lowest altitude of the hike- 4,600' which is 300' lower than the trailhead. The real ascent begins.
Section 2: Hobo Gulch Junction to Grizzly Meadows
At the junction with the Hobo Gulch trail, I went left or East and through a relatively flat section that parallels Grizzly Creek. On a map, it looked like the trail was right next to the creek but it actually stays several hundred yards away and thick brush separates the distance- this is worth noting if running low on water.
For the next 1.5 miles, the trail runs through a very thick and lush "rainforest" showcasing the extensive pine species emblematic of the Trinity Alps. Mt Thompson is one of the wettest and snowiest places in California which leads to such diversity. Even a novice naturalist like myself instantly recognized several hallmark species of the coast ranges.
This section was mostly flat and well-shaded. A nice respite from the previous ascent.
Further along, the trail begins the steady ascent to Grizzly Meadows. Although the trail is very clear, there's no signage or mileage along the way. I plodded along, nursed by intermittent streams for water sources and ever increasing views of Mt Thompson to the South.
From the Hobo Gulch junction (altitude ~4,600') to Grizzly Meadows (altitude ~6,100'), its another 4.2 miles by my measurements. From the trailhead, its about 7.4 miles, one-way. You know you've reached Grizzly Meadows when a glorious view of the waterfall becomes visible-
There's a fantastic few campsites near Grizzly Meadows. Note there's also a lot of bears; bring a bear canister.
Section 3: Grizzly Meadows to Grizzly Lake
I set up my campsite near Grizzly Meadows (altitude 6,100') and continued on with a lighter backpack. The waterfall itself was phenomenal and imposing- I didn't realize how much altitude I'd gain in the next mile. From Grizzly Meadows too Grizzly Lake (altitude ~7,300') and the waterfall crossing, its a gain of 1,200' over a mile.
The trail itself deteriorated to a herd path marked by cairns. Its clear mutliple paths through the talus field exist so I carefully made my way along. Just as the route looks as if it will ram into the waterfall, it takes a left turn and snakes its way up the slope.
While I had no trouble finding the path of least resistance of the West-facing cliffs, it was a little exposed and lose. Melt-water cascaded across the route making for some slippery climbing but it never exceeded a class II rating. Cairns marked the way every 10-20 yards so I never felt lost.
Once I finally gained the top of the cliff, the route lessened in steepness and a glorious view of the lake came into view.
Section 4: Grizzly Lake to Mt Thompson Ridgeline
Now at Grizzly Lake, Mt Thompson's incredible North face and glacier rose sharply over the lake. Dozens of cascades poured down its flanks in a thunderous cacophony. It would have been a perfect spot to camp for a few days.
I read differing accounts about climbing Mt Thompson from here. Some indicated the right-most cascade tumbling from the glacier, perpendicular to the outflow of the major outlet/waterfall is the best route. I didn't like the look of it- it was steep, brushy and wet.
I took a similar approach, walking along the North shoreline of Grizzly Lake but I used the ramp-like feature of rocks heading almost directly West to gain another 500'. This was class II hiking/scrambling and I had no trouble. Once I reached an altitude of roughly 7,600', I side-hilled along another 1,000 or so yards until I came to the glacier/permanent snowfield. In June, there was plenty of snow on the route which worked to my advantage- I just popped out my crampons and slithered up without problems.
I hope these photos help illustrate the route I took:
Crampons were invaluable in gaining the ridgeline. Slopes exceeded 60 degrees in some sections and I was glad I had an ice axe as well. On the return route when I ran into some similar peakbaggers at lower altitudes, nobody seem prepared for this section- they did not bring any traction, ice axes or poles. I think that's a mistake.
Once I stood on the ridgeline, the summit was just 500' feet above me.
Section 5: Ridgeline to Mt Thompson Summit
This final section was relatively straightfoward but took an unreasonably long time. Clearly I felt the fatigue of the day. At first I tried following the ridgeline directly but there's a lot of pointless up-and-downs and unnecessary scrambling that ate away at my dwindling light. Eventually, I settled on a path that took me about 50-75' below the ridgeline, just to the South.
I worked my way across talus, sandy rock and plenty of krummholtz before arriving at the final summit block. Up until this point, the most complex moves were class II and infrequent. The summit block itself is Class III. Its stuff that wouldn't be difficult at all in a rock gym or at sea level but at the end of a long climb and with some exposure, it felt challenging.
The precipitous summit of Mt Thompson had glorious views of the entire Trinity Alps. All the highest summits were visible as was most of the North Coast mountains in four counties and parts of Oregon. Two water bottles served as a summit register with only a dozen or so parties signing it each year. Many famous people in the peak-bagging world signed their names as well. Once you climb more obscure mountains, its just the same names over and over.
Altogether, from the trailhead to summit, I climbed almost 7,000' over about 10 miles.
Fortunately the descent was uneventful. I basically traced my way back across the same route and arrived at my campsite well past dark. I didn't like having to cross the Grizzly Lake outlet/waterfall after dark, then make the descent down the cliffs to Grizzly Meadows. However, I slowly and surely made my way down.
The next day was just a long walk out. I enjoyed the walk through the rainforest again to the Hobo Gulch trail junction and ran into a few parties along the way. Again, many had Mt Thompson as their destination but were clearly unprepared for snowfield travel. I wished them luck.
I made it back to the trailhead about 28 hours after starting- of course 28 hours includes the 6 hours of sleep I got as well. Exhausted and dirty, I rinsed off in a nearby stream and made the long drive back to Yreka.