Conservative decision making and disciplined terrain use is the name of the game when these tricky avalanche conditions persist. Check out the new Forecaster Blog @ avalanche.ca.
Weather Forecast
A weak system will slide down the coast and start to affect the Interior on Saturday bringing mostly light snowfall amounts up to 10 cm. Ridgetop winds will be light-moderate from the west, switching to a northerly flow by Sunday. Alpine temperatures will hover around -15 and drop to -18 later Sunday. Conditions will remain cold and dry through Tuesday.
Avalanche Summary
Natural avalanche activity has tapered off and skier/ rider triggered avalanches are the name of the game. On Wednesday, numerous skier triggered avalanches up to 1.5 were reported and I expect this to continue through the weekend. Remote triggering from a distance is still a concern.
Snowpack Summary
In some parts of the region a thin breakable rime crust exists near the surface. The upper 40-90 cm of storm snow is slowly consolidating into a slab above a touchy surface hoar layer buried mid-December. Below 2100 m this slab sits on a thick, solid crust/ surface hoar combo and acting as a perfect sliding layer. Persistent slabs will be touchy to the weight of a skier and rider, especially in wind effected areas where the slab is stiffer. Deeper in the snowpack is a hard rain crust with facets from early November. This is buried over 1 m down and is currently unreactive but triggering from shallow rocky, unsupported terrain remains a concern.
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.