Half Peak is sequenced with Quarter Peak to the north. One-way mileage and elevation gain are measured from the summit of Quarter peak. Round-trip mileage and elevation gain assume completion of the sequence.
From the summit of Quarter Peak 13,674, head back down the north ridge and drop back into the bowl/basin on the east side of Quarter Peak, below the summit at an elevation of about 12,800 ft. Traverse the boulder talus to the south side of the basin, (If you drop to about 12,600 ft., you can avoid a lot of the talus, walking just past the end of a couple of rock glacier tongues) then ascend back up out of the basin to the SW regaining elevation to around the 13,200 foot level or a minimum of 13,000 ft. (Probably best to stay higher.) Continue hiking SW over mostly tundra terrain laced with sheep trails and drop to the saddle between Half Pk and Quarter Pk at 12,940 ft, NW of Half Peaks summit.
Walk on up the steepening NW ridge of Half Peak, still mostly on tundra/grass and small rubble. Footing remains secure even though the slope becomes very steep. At about 13,650 ft., the east facing slope and ridge come to a rocky point. For the next 100 feet of hiking, you'll need to search for a route through some spires and breaks in the cliffs in order to reach the tilted summit plateau. This is what we regarded as the 3rd class section. We came up to the first cliff on the ridge and moved south a few yards towards a cairn that marked a route through a small saddle onto the SE side of the peak. We then turned right and worked our way through one steep couloir and around to another following some cairns - all this without gaining or losing any significant amount of elevation. In the second couloir, we climbed/scrambled upward until it crested back out on the NW ridge. Just below the top of the couloir, we turned left and climbed up a "V" shaped crack through the remaining cliff band and found ourselves standing on now easier ground. This last maneuver required a short amount of hand-over-hand scrambling in order to get through. Our kids managed it fine with no rope or protection but there's about 30 feet of climbing that was somewhat exposed. Some inexperienced persons may desire some protection here. Walk on to the large, flat, sloping summit of small scree and sporadic tundra. The actual summit will be toward the NW end.
Enjoy the Half Peak summit and take some time to peer over the sheer north face. There's still a nice view of Sunshine/Redcloud to the north and the Grenadier Range to the south. To descend, you can retrace your path back down the NW ridge to the saddle at 12,940 ft. If you do so, keep in mind that descending an exposed down climb can be more frightening than going up. Another route down would be to follow the south ridge of the peak all the way down past the narrow bottleneck and rocky section, onto the broad south-facing slope. The bottleneck section is short with some entertaining scrambling and modest exposure in points. Stay either on the ridge or the west side where you may find some trail to navigate through. Continue down the slope and follow the drainage that begins to form. At about 12,450 ft. elevation, you should intercept the Continental Divide/Colorado Trail. Follow it back to Cataract Lake and or your campsite up above the lake.
Links to other information, routes & trip reports for this peak that may be helpful.