Very dangerous avalanche conditions exist. Manage the uncertainty around buried weak layers by sticking to low-angle non avalanche terrain and avoiding overhead hazard.
Buried weak layers are most concerning at treeline elevations. Small avalanches may step down to this layer resulting in very large destructive avalanches.
A new storm slab will bury the persistence slab and add additional load. There is potential for this storm slab to step down to the persistent slab depths.
Strong southwest winds will transport new snow onto lee aspect terrain.
No new avalanche observations or reports on Friday or Saturday at the time of publishing. Thursday was very active for avalanche observations and occurrences. Many persistence slab avalanche where triggered during explosive work and where large (size 3) . These avalanches had crowns greater than 100 cm in depth and 100 to 200 meters wide. A few avalanche where remote triggered by skiers.
Storm snow amounts near days end exceeded 40 cm with another 20 cm forecast. This new snow overlies a variety of surfaces including surface hoar. Expect strong south winds to strip snow from ridgelines and exposed features and deposit new snow into deep pockets in lee aspect terrain.
Under the new snow an estimated 120-160 cm of progressively resistant or 'right side up' snow is continuing to settle above the problematic crust/facet/surface hoar layer beneath it. This layer continues to show sensitivity to human triggers, and is most concerning at treeline elevations where weak grains like facets and surface hoar are more easily preserved.
Saturday night
Cloudy with snowfall bringing 10-20 cm of new snow. 40-60 km/h southwest alpine wind. Treeline temperature around -4 °C with freezing level about 1100 m.
Sunday
Cloudy with continuing snowfall bringing 10-20 cm of new snow and 2-day totals to 40-60 cm. 40-60 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1300 m.
Monday
Cloudy with snowfall bringing 5-15 cm of new snow. 40-50 km/h southwest alpine wind. Treeline temperature -3°C with freezing level around 1200 m.
Tuesday
Cloudy with snowfall bringing 5-15 cm of new snow. 20-30 km/h southwest alpine wind. Treeline temperature -3°C with freezing level around 1200 m.
More details can be found in the Mountain Weather Forecast.
