Recreational Observation

Approached from Surprise Lake to Surprise Gap and up the East shoulder.

Jan. 1, 2019, 1 p.m. PST

Weather: Light overcast, ceilings ~7500', Northerly winds at ridgetops ~20 kt, temperatures in the mid to high 20's

Snowpack: Medium density snow, 8" of ski penetration, 12-24" pole penetration, rain crust observed up to 4500', wind transport of crossloaded slopes, non reactive wind slabbing of 8" on S aspects at ridgetops, no signs of instability up to the avalanche incident, no snow pit analysis performed

Area Description: N-NE 40-45 degree chute, Surprise Mtn, 6300'

Avalanches: Upon skinning across the top of a 50m wide chute funneling into a 10m choke, a 12-14" crossloaded windslab was triggered (R2, D1.5). The slab ran ~800 ft into the valley floor and was 20m across and 30m long. Noticeable staunch wall that was entrained indicating an isolated wind slab. It was triggered from the ridgeline above, but the average slope angle was 35+ degrees. Both members of the group were nearly caught.

Observation by Sean O'Neil

Did you see any avalanches? Yes

Did you trigger any avalanches? Yes

Was anyone caught in an Avalanche? No