We are in the middle of a storm with dangerous avalanche conditions. Ongoing wind and precipitation will cause stability to deteriorate throughout the day.
Weather Forecast
Heavy precipitation expected for today with snow fall amounts up to 40cm by this evening. Strong SW winds gusting to extreme near ridge top. Freezing levels rise to 1450m this afternoon with alpine temperatures reaching a daytime high of -5. A northwesterly flow will follow the passing of the storm this evening bringing dry and cold conditions
Snowpack Summary
25cm of new, unconsolidated snow fell overnight. Strong S-SW winds accompanied the snow fall and heavily loaded lee features and aspects, forming deeper slabs. New snow overlies a crust below 1700m. The November 11 surface hoar layer is present above 1800m with localized distribution. An isolated basal weakness is capable of large slides.
Avalanche Summary
Several avalanches from steep terrain were observed in the highway corridor, running up to size 2.5 with moist debris terminating halfway through their run-out zones.
Confidence
Intensity of incoming weather systems is uncertain
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.