March 6, 2021
March 7, 2021
Zone or Region:
Near Whitehorse Mountain
Did you trigger any avalanches? Yes
Was it intentional? No
Size 1: Relatively harmless to people
D1-D1.5 wind slab failure about 10 inches or so deep, 20 feet wide, ran 300-400 feet out. The soft wind slab broke on an icy crust. Probably a rain crust from earlier in the week. Did not get any pictures of it.
We were skiing in a group of 3 starting from 1200 feet and skinning through about 7 miles of terrain up to a peak near Darrington. We observed stable snow conditions below and near tree line all day, digging hand shears as we moved up and consistently discussing conditions. As we gained elevation closer to an exposed ridge we began to notice 3 inches or so of soft, less cohesive recent snow. As we gained elevation close to the summit, the soft non-cohesive recent snow began to increase in depth to about 8 inches or so. We reached the summit and decided to ski the east facing slope. Our ski partner descended a ridge nose, took a small turn on the north side of the ridge and caused a small wind slab to release underneath them near the summit. They were skiing close to the ridge, so were not caught. The remaining group members descended along the ridge that had slid and then skied a protected east facing slope. East aspect conditions were noticeably more stable and not wind loaded.
We observed active wind loading on the north side at the exposed summit around 4800 feet. Evidence of heavy wind loading on a nearby ridgeline.
Did you observe any avalanches? Yes
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few trees
Observed multiple recent large wet loose avalanches off of a big cliff band. They probably ran this past week with increased temperatures and sun. We had minimal concerns of hang fire moving across the debris field since the temperatures were decreasing throughout the day and most of the snow had already released from the cliff band. We noticed some dry slough releasing from pockets along the cliff band at one point, but it was a small amount.