A Special Public Avalanche Warning is in effect for this region.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
A last pulse of 5-10 cm snow with easing SW winds and a 1000 m freezing level is expected on Saturday ahead of a cooling and drying trend starting Sunday morning. Cloudy skies, light winds, cool temperatures and a few flurries may give way to sunny skies on Sunday/Monday. For more details check out https://avalanche.ca/weather.
Avalanche Summary
Numerous size 1-2 slabs were triggered naturally and by skiers over the last few days. Many of these failed at and below treeline, on buried surface hoar, about 20-40 cm deep. Many of these were triggered remotely, highlighting the volatility of the persistent slab. An increasing number of wind slabs have also been failing at alpine/ treeline elevations, and also running on surface hoar. It is likely that a natural avalanche cycle occurred on Friday in response to the warm, windy storm.
Snowpack Summary
The recent storm has created storm slabs in many places and wind slabs on features lee to the south. This has also added load and stress to the already volatile persistent slab. This 40-90 cm persistent slab overlies a variety of surfaces including large surface hoar, sun crusts, and facets. The persistent slab is ripe for human and natural triggers and is especially touchy at and below treeline. The mid and lower snowpack are generally well settled and strong.
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.
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.