The storm continued overnight, depositing more snow with strong winds. Good group management, minimizing exposure to overhead hazard, and conservative terrain selection are highly recommended.
Weather Forecast
As the storm exits the region we should get lingering flurries this morning, with moderate winds shifting to the NW as an arctic ridge of high pressure moves in. We may see some sunny breaks this afternoon, and Thursday looks sunny and cold with temps dropping to -20 overnight. Friday will be cloudy and snowing with strong SW winds at ridgetop.
Snowpack Summary
80cm of storm snow sits over a variety of surfaces from December 8th like surface hoar lower down, facets and variable wind slabs at higher elevations. Strong winds have formed windslabs and wind loaded pockets above treeline. Below this are 2 persistant weak layers and the snowpack is facetted. As the load increases these layers may wake up.
Avalanche Summary
A widespread natural avalanche cycle continues. Most were initiated in the alpine and at treeline, running well into runouts, but several triggered slabs below treeline. Along the highway, 1 size 3.5, 4 size 3 and 20 size 2 avalanches were observed yesterday. On Monday skiers reported large natural avalanches occurring up the Connaught drainage.
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.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.