Recreational Observation

Skinned up FS road to intersect bootpath up NW ridge to summit. Planned to ski west facing slope just N of the summit.

Dec. 23, 2017, 10:30 a.m. PST

Weather: Sunny, clear, cold ~ 20 deg. Wind gusts around 15 mph towards the summit.

Snowpack: Minimal in the trees heading up the NW ridge until about 4500 ft. Increasing depth above, varying in places depending on windloading.

Area Description: Humpback Mountain

Avalanches: We were about 20 yds below the summit on the W side with one switch back to gain up onto the ridge. We were booting up, terrain was not conducive to skinning. There was a minor cornice on the ridge above and ahead of us, and the wind was blowing around 10-15 mph loading the west side. We were attempting to get onto the ridge before being near the cornice. The slope we were on making the switch back was moderately treed. I made the switchback, took a couple steps, saw a shooting crack out ahead of me, took one more step to reposition, and the slab broke about 10ft above me, about 2ft deep. I had a group of 2 trees just below me which I was able to grab on to and hug, letting the slide pass by, covered me to around my thighs. My parter was about 20 yds below and to the side, the slide took a path to the side of him. It slid for 50 ft or so before dispersing in the trees and stopping. Only got the pictures of where the slide broke above me.

Latitude: 47.373652

Longitude: -121.495657

Did you see any avalanches? Yes

Did you trigger any avalanches? Yes

Was anyone caught in an Avalanche? Yes