60-80cm of new snow in the last 2 days has changed the landscape significantly. This new snow overlies surface hoar or a sun crust; both problematic layers that promote poor bonding and easy sliding.
Human triggered avalanches are possible to likely on slopes that did not previously avalanche during the storm.
65cm of snow and strong SW winds in the last 48hrs have created a storm slab. This new snow sits on a surface hoar layer in sheltered zones, and a sun crust on steep, solar aspects; both concerning, persistent sliding layers. This storm slab can/will be triggered by riders where it is cohesive.
The natural cycle has tapered off with the passage of the storm, revealing numerous sz 2-3 avalanches from all aspects failing at the base of the storm snow interface.
Artillery control produced excellent results on Tupper and Macdonald Sat night, with most shots producing sz 2 to sz 3 avalanches from steep start zones, running out onto valley bottom fans. Debris moved fast, likely picking up speed and mass on the buried surface hoar.
Up to 65cm of new snow sits on a sun crust on steep solar aspects. In sheltered locations, this new snow sits atop large surface hoar. Strong winds Sat PM will have promoted surface slab conditions on exposed Treeline and Alpine slopes.
There is a dense, well-settled mid-pack without any significant weak layers.
The Nov 9 crust is down 1-1.5m. The base of the snowpack is comprised of several dense, melt-freeze rain crusts formed in October.
A ridge of high pressure will bring calmer conditions.
Tonight: Cloudy, isolated flurries. Alp low -10°C, light W winds, Freezing Level (FZL) valley bottom.
Mon: Cloudy with sun and flurries, Alp high -10°C, light W winds, FZL 600m.
Tues: Cloudy with sunny periods, Alp high -4°C, light W winds, FZL 800m.
Wed: Clouds, isolated flurries, Alp high -4°C, light SW winds, FZL 1300m.
