Tricky times out there. The alpine is not the place to be for the next while. Treeline is also a complex place at the moment. Travel cautiously, don't blindly trust the snowpack and avoid overhead exposure.
Weather Forecast
A South West flow will bring another pulse of snow overnight tonight. Expect about 5cm. Alpine winds will be around 80km/hr from the SW. As the storm plays through, the winds are expected to drop slightly. Alpine temperatures will also drop to -10 during the day.
Avalanche Summary
Lots of windslabs pulled our during the storm. Many were already blown in. Most were in the alpine and on easterly aspects and averaged sz2. There was also a report a skier remote sz2, 120cm deep and ran quite far. Specifics are unknown. We are definitely in the human triggered portion of this avalanche cycle.
Snowpack Summary
The recent storm snow has been widely redistributed by the strong SW winds. In sheltered areas at treeline, there is up to 40cm and the alpine varies from 40-100cm depending on wind exposure. Needless to say, the alpine is completely covered in new windslabs. Treeline is a bit more forgiving in terms of windslab distribution, windslabs aren't as widespread. The Dec 10th surface hoar/facet layer is down 20-30 at treeline. As far as surface hoar is concerned, we did find it, but it was actually hard to track down. Sheltered areas at treeline seem the most likely, but there could be pockets in more open terrain. Facets on the other hand, are very easy to find- nothing new there! We'll nail this layer's character down better as more observations are made. The deeper crusts, are mostly facetted out, but seem to be reasonably well glued together in low angle terrain.
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.
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.