Quick report
- Cracking
- isolated
- Collapsing
- widespread
Widespread collapses were observed in both wind-loaded and sheltered terrain. A thunderous collapse was enough to give pause while skiing next to a steep roll over. I observed several small slides within the recent snowfall, and one recent very large avalanche in wind loaded alpine terrain.
Below 9,000', collapsing was more frequent, with the most collapses observed near 8,000'. Along ridgelines, cracking was observed in wind-loaded terrain, isolated to freshly formed wind slabs. The cracks did not extend beyond the tips of my skis. While skiing out, I triggered a thunderous collapse on a S-facing slope. The steep roll below didn’t slide, but I watched the slope settle about 50' down slope from me. In the headwaters of Cabin Ck., I observed a very large natural avalanche in alpine, wind-loaded terrain. The avalanche broke an estimated 1–3' thick and 800' wide.Weather
- Air Temp
- Teens
- Cloud Cover
- scattered
- Wind Loading
- previous
- Recent Snowfall
- 5-10
- Snow Avail For Transport
- moderate amounts
The temperature at 9:30 AM in the parking area was 14°F. Skies were partly cloudy, increasing by sunset. Ridge top winds were calm.
Snowpack
New snow: 5-10 cm of snow fell in the last 24 hours, and ~40 cm since 12/25. While subtle, there is a weak interface below the most recent storm, and produced unstable results in stability tests. ECTP10 on decomposing snow and small grain facets. (S, 9200')
Mid-December weak layers: These weak layers were easy to find and most prominent below 8500', producing more widespread collapsing and poor stability test results. (HS: 107, ECTP11 @ 66). Above 8500' collapsing was less frequent, however stability test still yielded unstable results, (HS: 134, ECTP 20 @ 68)
Avalanche
- Size
- D3 R3
- Aspect
- E
- Trigger
- N
- Elevation
- 9800 ft
I observed a very large avalanche in east-facing alpine terrain, likely occurring near the end of the most recent storm. The avalanche failed and propagated on mid-December weak layers. Additionally, I saw several recent small avalanches in wind-loaded terrain.