Cooling has improved avalanche danger, but deep avalanches remain a possibility, especially in thin snowpack areas at high elevations.
Weather Forecast
A few cm snow are forecast for Friday night. A second pulse of snow (5-15 cm) is due on Sunday. Freezing level is at valley floor during the nights and rising to around 800 m by day. Winds are generally light for the next three days.
Avalanche Summary
As the temperature drops I expect that avalanche activity will slow down. The recent snow, rain, and wind were a great test of buried persistent weaknesses in the snowpack and resulted in a widespread avalanche cycle. The mid-January surface hoar layer was responsible for the majority of the recent avalanche activity although there have been reports from the Selkirks of occasional releases to ground and on the mid December layer.
Snowpack Summary
Variable crusts exist at most elevations, ranging from breakable to supportive. Above about 2300 m, you might find some wind-affected snow and cornices. The mid-January surface hoar remains a concern and can be found down between 30 and 80 cm. In some locations it has reportedly gained quite a bit of strength, but in other spots it still produces sudden (pops) results in snowpack tests. The mid-December surface hoar layer is now 80 to 140cm below the surface and has become unlikely to trigger (but still has the potential for a large avalanche if triggered).
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.