Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Synopsis: The pattern calms down a bit as the flow becomes more zonal (westerly). A few weak features impact the coast through the weekend.Saturday: Freezing Level: 1200m Precip: 3-6mm/4-12cm Wind: SW Moderate gusting Strong.Sunday: Freezing Level: 700m Precip: trace Wind: NW, Moderate.Monday: Freezing Level: 1000m Precip: 10mm/10-20cm Wind: S, Light.
Avalanche Summary
Evidence of a natural avalanche cycle to size 2.5 is surfacing as professionals begin to venture further afield. Soft slabs failing within the storm snow with crowns to 40 cm illustrate the current problem well.
Snowpack Summary
The storm has delivered around 60 cm of heavy snow at upper elevations while simultaneously raining as high as 1900m as freezing levels fluctuated during the storm. The new snow has been settling rapidly and is slowly bonding to the previous snow surface, which includes faceted snow, surface hoar, and/or a crust. This interface is most concerning where the surface hoar is sitting on a crust on previously sun-exposed sheltered treeline slopes. Cool temperatures should limit natural avalanche activity but I suspect the snowpack could still use a bit of time to adjust to it's new load. We also need to gather more information on this interface before we think getting into the bigger terrain. Below this interface, the snowpack is strong and well settled.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.