ACMG Ski Guide Eric Dahlberg and myself took a group to the McDermott cabin from Jan 3rd to 6th for an AST 2 course.
We accessed the cabin via Tunnel Creek on the 3rd, with poor visibility and freezing rain in the parking lot. Travel conditions from the parking lot to the cabin were good. A thin crust up to 1900m formed during the morning of Jan 3rd over the previous night's storm of approximately 15cms, however, it does not exist where the forest canopy shelters the snow surface. At one of the Planetary Peak south-aspect avalanche run-outs we encountered debris from a recent size 2.5 avalanche (likely from Jan 1 precip-warming event).
On Jan 4th we woke to strong winds and poor visibility. We travelled up the west aspect of Planetary Glades to gain the ridge. At ridge top, Eric stepped on a wind-lip that sent snow onto the east facing slope below and triggered a size 2 wind slab, 60m wide x 25cm deep. It ran to the top of the run out. We also observed debris from 1 natural wind slab on the same aspect, and another on the east face of McDermid size 2.5. Test pits at 1920m, W aspect, showed 5cm wind affected surface on the thin rain crust from the previous morning. Compression tests had consistent moderate to hard, resistant planar results, down 40cm immediately below the Christmas rain crust, which was less than 1cm thick. No results with extended column tests.
On Jan 5th we traveled from the hut up toward Race Car Mnt, with a max elevation of 2080m. Test pits at 1970m, NE aspect, showed consistent moderate to hard resistant planar results immediately below the Christmas rain crust down 40cm (again) with very spotty, rounded surface hoar found in one pit. Extended column tests were inconsistent with propagation across the entire column in the moderate tap range to no result. On the way back to Tunnel Creek hut, we observed numerous natural windslab avalanches on the N-NE side of Race Car Mnt with crowns up to 1m deep. In some areas the wind had stripped the surface back to the Jan 3rd rain crust around 1700m, but overall skiing was good and the road exit was carve-able.
