Trinity Alps High Route Part II: Mirror Lake, Caesar Peak & Thompson Peak

Part II of the three part series on the Trinity Alps High Route fastpack focuses on the section from Sawtooth Mountain to Thompson Peak. The other parts of the series:

• Part I including Little Granite Peak, Sawtooth Peak, Alpine and Smith Lake
• Part III including Wedding Cake, Mount Hilton and Boulder Creek lakes

Photos here. The section covered in this post is probably the most remote and rugged of the entire route, particularly the section from Kalmia Pass to Mirror Pass. After downclimbing the scramble section of Sawtooth Mountain, one is treated to a walk across the peak’s massive east face, which is a gently sloping granite apron. The granite is smooth and the travel is generally easy until one reaches a ridge that separates Devils Canyon from the Stuart Fork of the Trinity River. Along this ridge is a small notch called Twin Pine Pass that enables passage to the other side. This pass is quite miraculous since virtually anywhere else above or below this pass would require some technical climbing. Accessing this pass is straightforward if you aim to gain the ridge west of the pass and then drop down into the pass from the ridge. There are a few ways to gain the ridge and most will contain a few scrambling moves.   From Twin Pine Pass, there is a section of talus hoping before one reaches another marvelous section of smooth granite slabs where efficient progress can be made.  Above these slabs is a wonderful glacially sculpted ridge and below the slabs is a tremendous view across the canyon to Mirror Lake and Caesar Peak. As one moves west across this section of pristine granite, Mirror Lake grows larger and the views keep improving. Ultimately, the easy slab walking ends and one must begin an ascent toward Kalmia Pass. It may be tempting to descend from Kalmia Pass directly into the basin between it and Mirror Lake, but this is not advisable due to dangerous cliffs and fields of unstable talus. Instead, there is a broad sloping ledge sandwiched between two cliff bands that provides a relatively efficient and safe route to Mirror Lake. From Kalmia Pass, descend northwest along alp slopes and talus to the ledge and begin traversing across with cliffs above and below. The views along this traverse are stellar and include Sapphire Lake with Sawtooth Ridge towering behind. The ledge is not flat so there is quite a bit of sidehilling and a couple washouts to cross that include steep hardpan so caution is necessary at several points of the traverse. Keep following the ledge for longer than you might assume, generally maintaining elevation and evening ascending a little as Mirror Lake comes into view immediately below and the lower cliff band reaches higher. Eventually an obvious gully comes into view with Mirror Lake directly below. This weakness in the cliffs is the ticket to reaching Mirror Lake without hazardous down climbing through cliffs. Follow the gully down and then move left onto granite slabs and benches for the last part of the descent to lovely Mirror Lake. Aptly-named Mirror Lake is tucked into a granite bowl beneath the grand cirque that forms the headwaters of the Stuart Fork of the Trinity River. This lake is a wonderful spot and extremely photogenic. Enjoy the lake since the ascent from Mirror Lake to Mirror Pass is fairly long and arduous gaining 1,400 feet in short order. The main idea is to reach a bowl beneath Mirror Pass that is ~7,800 ft. When ascending the granite slopes and shallow gullies north of Mirror Lake, one approaches what appears to be a headwall but a diagonal ramp leads left to right to a forested ridge that provides access through the headwall and to the bowl. From the bowl, ascend talus slopes to Mirror Pass which is another miraculous crossing where cliffs are present on both sides of the pass but the pass itself is basically a walk over. It seems possible to ascend Caesar Peak via its east ridge from beneath Mirror Pass but this description is for the easier class 2 ascent via the North Ridge.  To gain the north ridge traverse at 8,000 feet on granite slabs and moraine debris. A permanent snowfield once existed here but all that remains is a few chunks of ice beneath the towering cliffs of Caesar Peak’s northeast face. After ascending the glacial moraine the route reaches another pass that separates the Little South Fork Salmon River from Grizzly Creek. From this pass Caesar Peak is less than a thousand feet up. One can stick to the north ridge proper from the bottom or take pleasant granite slopes west of the ridge and use one of the many small chutes to gain the ridge higher up. Caesar Peak features a commanding view of the region including Mirror Lake, Sapphire lake and Sawtooth Mountain to the south, Thompson Peak to the west and Grizzly Lake to the north. The cirque above Grizzly Lake can easily be traversed to continue the route between Caesar Peak and Thompson Peak, but Grizzly Lake is one of the highlights of the route and worth the fairly large elevation gain and loss necessary to reach the shores of the lake. The spectacular lake situated in a rugged granitic cirque with deep blue waters and clumps of firs. One of the most amazing aspects of this lake is its outlet waterfall which tumbles over large cliffs only a few feet away from the lake. Not much water is present late in the summer but this must be a spectacular sight in early summer and worthy of an trip earlier in the season to view this waterfall in its full glory. There are several good camp spots on the north shore of Grizzly Lake with stunning views of the granite cirque including Caesar Peak and Thompson Peak. From Grizzly Lake it’s a fairly straightforward climb up slabs and talus to notch on the northwest ridge of Thompson Peak. In the upper reaches of this climb is a faint trail that provides easier passage through the scree and rocks. From the notch in the ridge, instead of traversing into the Rattlesnake Creek basin one can ascend the northwest ridge of Thompson Peak directly to the summit. Where the boulders became large and awkward, move to the south side of the ridge and continue up to the summit with a few class 3 moves along the way, including the summit block which is a collection of very large boulders and some fun bouldering moves. The 360 degree panorama from Thompson Peak is amazing, particularly down to Grizzly Lake and the Thompson Glacier. While the glacier is now only a few acres in size, there still appears to be crevasses and ice movement. Hopefully the glacier makes it through this drought, but I’m not too optimistic about its long term survival. From Thompson Peak the view south is equally impressive and includes much of the remainder of the route across the broad granite face to Mount Hilton, Sawtooth Mountain and the Canyon Creek Lakes drainage. The section from Thompson Peak to Mount Hilton to Boulder Lakes will be covered in the last segment of the Trinity Alps High Route series.