OverviewThe West Ridge of Mt. Robinson is a high quality route that should be done more often. Though it doesn't gain much elevation, it is an enjoyable ridge scramble with quality moves and rock, high exposure, and complex routefinding. The views are excellent as well and the many hidden catwalks that offer passage through vertical terrain are fun to stitch together. I'd rank it as one of my favorite scrambles in the Sierra.
The rating is class 3 to easy 4th if you stay on route. If you get off route, it can easily become 4th to 5th class. The route took us just over an hour to do to the summit, about 2 hours round trip.
Getting ThereApproach via North Fork of Big Pine from the Glacier Lodge trailhead. Take the trail to Sam Mack Meadows and climb the right-hand chute (cl. 2-3), bypassing a large boulder on the right. This section can have a lot of water and some ice buildup in later season, and sometimes the easier variations involve climbing through spaces in the rocks. Next, follow the series of slabs in the drainage as you make your way to the Thunderbolt Glacier. When you reach the first lake at 11,790', ascend towards the right, passing Sam Mack Lake on your right as you aim for the saddle between the E Ridge of Mt. Agassiz and the W Ridge of Mt. Robinson. The route starts here.
Another option could be to hike to 5th Lake and then head cross-country up the drainage that empties there. This may be a bit more distance, but not as steep. This might not be as good as it looks to require a lot more boulder-hopping, while the former approach has a lot of nice travel on slabs and meadow.
Though it is a bit of a trek, if you're camped out on the moraine of the Palisade Glacier, you can just traverse on moraines towards the saddle, making this route a nice one to do if you're already camped out in the area for some other climbs. It could be a good pre-climb acclimatization outing, done on the same day as the approach to camp. There is some elevation gain and loss, but it's not too bad. Expect 1-1.5 hours to traverse to the route from the north (right) lateral moraine of the Palisade Glacier if there isn't snow covering the rocks. Great snow cover should make the approach faster.
Route DescriptionDue to the complexity of the route, I've kept things simple by describing it in numbered sections that correspond to the annotated photo below.
In general, the route follows the south side of the ridge.
Begin ascending the ridge from the saddle. As the ridge becomes more rugged, gradually veer right (south) to traverse a system of broken ramps/ledges about 50 ft below the crest. Stay lower to avoid section (1) if you wish, but I recommend the higher variation.
1. When the ridge crest becomes blade-like and the ramps seem to end, climb up to a notch in the ridge and down a class 3 slab before continuing on a new ramp system on the right (south) side of the ridge.
2. Ascend to a notch in the rib extending off of the main ridge. Climb beneath the chockstone and down a chute to continue traversing (cl. 3)
3. Eventually an exposed hand traverse is reached. Footholds disappear as the ledge constricts. Downclimb below this section, traverse, then climb back up to the main ledge system.
4-5. The route cliffs out, but chutes above offer passage to another hidden ledge system. Climb 2 steep chutes. The first is class 3 (4), and the second is longer, steeper class 3 to easy class 4 (5). The rock in this chute is slightly loose but those rocks are easy to avoid. You can tell which chutes to take as they lead up to the ridge at a point between two spiky gendarmes. The one on the left is especially pointy.
6. Once you are near the ridge, do not continue to the crest. Instead, climb right through one notch, down a short exposed slab to another more hidden notch. This accesses a new hidden catwalk system. In general, from here on out, follow weaknesses along a horizontal dike. Eventually you will scramble up near some diagonal dikes on a distant gendarme.
7. While following the horizontal dike, scramble up and right on an exposed slab (cl. 3-4) and around a corner.
8. Still following the dike, scramble up to and through an exposed hand traverse (cl. 3). Climb above it, then down onto a slab with subtle footholds while using the thin horizontal lip for handholds, then climb up and out of the traverse.
9. Turn left and scramble up a series of class 3 chutes to reach a notch in the main ridge. This is done just short of the gendarme with diagonal dikes. Once on the ridge crest, scramble up broken blocks on the crest, veering slightly right as you near the summit.
10. Just short of the summit a headwall with steep dihedrals blocks progress. Turn right and scramble through another notch. This leads to class 2 ledges that wrap around to the East side of the summits, threads between the Middle and East Summit, and onto the North side of the ridge as you wrap around to the Middle and West summits.
Take care to look behind you as you scramble up this route, as it looks different in reverse and is just as difficult to return on.
DescentRetrace your route on the West Ridge.
If you are doing this scramble as an outing via Sam Mack Meadows, it would probably be faster and easier to descend the class 3 NE Face of Mt. Robinson and drop directly into Sam Mack Meadows or link up with the trail lower down. I haven't done this route, but my best guess is the line descends NE from the summit and enters a broad chute where the topographic maps indicate a permanent snowfield. This line looks to have easier scrambling than the West Ridge as well.