Observations
Turnagain Arm: Penguin
Obvious signs of instability:
- D1.5 human triggered wind slab avalanche at 3800′ SSW aspect (ridge line)
- A few distinct collapses (whumphs) between 2500-3000′
- Short shooting cracks in deeper wind loaded areas
Weather:
- Sub-zero temps (-7*F)
- Moderate NW wind
- Partly cloudy skies
Surface conditions:
- ~20″ very soft and light snow from trailhead to 3000′ in the west bowl (sheltered from wind)
- Variable, wind-affected snow above 3000′ in the west bowl (1F rippled wind drifts & P exposed old wind slab)
Snowpack:
- Below 2000′: minimal to nonexistent base (~20″ recent snow with unsupportable, older faceted snow beneath)
- Above 2000′: old wind slab, becoming more supportable with elevation gain, under ~20″ of new snow (collapses occurred between 2500′-3000′ where old wind slab was less supportable)
- Varied persistent weak layers underlying old wind slab above 2000′ (primarily facets and depth hoar)