Strong winds will help build fresh slabs as flurries accumulate through Sunday.
Expect to find the deepest and most sensitive slabs in lee and cross-loaded features.
A November crust/facet layer exists deep in the snowpack. Conditions have lent well to cleaning out and stabilizing the problem, but it may still be possible to trigger, particularly in thin-to-thick areas in the alpine.
Expect the storm slab problem to increase in depth and reactivity as more snow accumulates with strong winds. Slabs will likely be larger and more reactive in northerly, wind-loaded terrain.
On Friday, explosives triggered size 1-2 storm slab avalanches, which failed about 20-40 cm deep within the recent storm snow. The few size 2 avalanches were triggered in steep, wind-loaded lee features.
On Thursday, avalanche control work triggered reactive slabs in wind-loaded, northerly terrain, up to size 1.5. Riders found reactive slabs in the immediate lees of ridgetop features, up to size 1.
Strong southerly winds have left a variety of surfaces - wind slabs and loaded pockets in lee features, scoured rock in open terrain, and storm slabs and softer snow in sheltered areas.
Approximately 30 to 60 cm of wind-affected storm snow has accumulated through this week, and covers a melt-freeze crust is present at elevations of 2200 m and below. The depth of this crust is highly variable due to extensive recent wind transport.
A crust with associated facets, formed in mid-November, is buried an estimated 80 to 150 cm deep. This layer remains a concern in alpine terrain where it has not been capped by a strong overlying crust.
Saturday night
Cloudy. 5 to 10 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Sunday
Cloudy. 10 to 30 cm of snow. 40 km/h south ridgetop wind. Treeline temperature -3 °C.
Monday
Cloudy. 20 to 40 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -5 °C.
Tuesday
Mostly cloudy. 15 to 25 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
