Saturday`s danger ratings are based on light snowfall overnight Friday and Saturday. If new snowfall amounts are upwards of 15cm in your area, actual danger ratings may be higher.
Confidence
Fair - Intensity of incoming weather systems is uncertain on Sunday
Weather Forecast
Saturday: Mostly light snowfall with moderate westerly ridgetop winds. Freezing level around 1400 m.Sunday: Heavy snowfall with strong westerly winds. Freezing level around 1400m.Monday: Light to moderate snowfall with light southwest winds. Freezing level dropping to 1000m
Avalanche Summary
No reports of recent avalanche activity have been received. I would expect a new round of storm slab activity with weather forecast for the weekend.
Snowpack Summary
Total snowpack depths range from 110 to 160cm at treeline across the region. On the surface a newly developing storm slab covers a variety of old surfaces which include: old wind slabs at higher elevations, melt-freeze crusts on previously sun-exposed slopes and surface hoar in shaded terrain.In the mid snowpack you may find a layer of surface hoar buried in mid-November ranging from 50-90cms in depth. An October crust/facet combo exists near the base of the snowpack. These persistent layers are slowly becoming more difficult to trigger. However, they have the potential to cause large and destructive avalanches, and may 'wake-up' with the increased load of new snow forecast for the next few days.
Problems
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.
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.