Conditions Report: Half Dome – Slabs approach, Tis-sa-ack

Northwest Slabs Rescue

Last week, a climber was seriously injured while hiking up the Northwest slabs (“Death Slabs”) approach to Half Dome’s Northwest Face. Near the middle of the approach the climber was navigating a loose, boulder filled gully when a rock slid onto them. Yosemite Search and Rescue conducted a rescue through the night to bring the climber back to the Valley floor and medical attention.

In July, 2015 a significant rockfall from the Regular Northwest Face route sent shrapnel down the slabs approach. Recently deposited talus is typically less stable than older talus.

Tis-sa-ack Conditions Report

On August 25th, 2018 climbers on the route Tis-sa-ack encountered a massive exfoliation flake that “popped and cracked” as it was climbed. The roughly 300 foot by 150 foot flake prompted the team to descend immediately.

The team reported that what the topo notes as a C2 thin section is now a 3” crack, and a 3-6”crack is now a 40 foot sustained 9” crack.  5.9 loose flakes on the topo are no longer present on the route, potentially having fallen behind the flake. This is indicative of an actively exfoliating feature.

The flake is above the Northwest slabs approach and descent.  Users of the slabs approach may want to factor these conditions into considering their approach, descent, and bivy locations. Climbers seeking to ascend any route on the face of Half Dome should be aware of the high prevalence of exfoliation flakes and rapidly exfoliating features on the face.

Alternative approach and descent could be made by hiking up the John Muir Trail and descending to the Northwest Face from the northeast shoulder.