Regions
Northwest Inland.
Confidence
Fair - Due to limited field observations for the entire period
Weather Forecast
Friday: Light to moderate snowfall with 10-15cm of accumulation, freezing levels as high as 800m, and strong southerly winds. Saturday and Sunday: A mix of sun and cloud with isolated light flurries, freezing levels as high as 1100m, but dropping to 500m overnight, light easterly winds gusting moderate with flurry activity.
Avalanche Summary
Reports from Wednesday include evidence of Tuesday's natural avalanche cycle with wind slab avalanches up to Size 2.5 failing within the storm snow on steep terrain features. One Size 3 cornice-triggered persistent slab avalanche stepped down to the surface hoar buried a month ago.
Snowpack Summary
15-35cm of recent snow is generally bonding well to the previous snow surface, which includes a crust, facets and/or surface hoar. Strong westerly winds created widespread hard and soft wind slabs in exposed areas, which are reactive to human triggers on steep wind-loaded rolls. Below treeline, the surface snow is undergoing daily melt-freeze cycles with the upper metre of snow becoming wet and cohesionless by mid-afternoon. Concerns remain for a patchy persistent weakness buried a month ago, and deeper in the snowpack, basal facets may become a concern with continued mild temperatures. Cornices are well-developed and could easily become unstable during periods of warm weather or direct solar radiation.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.