Conditions change with elevation. Avalanche problems are lingering in the alpine while a widespread melt-freeze crust will make for challenging riding at lower elevations.
Confidence
Poor - Due to the number and quality of field observations
Weather Forecast
A ridge of high pressure will prevail through until Saturday over the southern half of BC, leading to mainly sunny skies in the mountains with extensive low cloud in the valleys. The north of the region may see some light precipitation on Friday as a front moves over the north of the province. Winds will be light through the forecast period.
Avalanche Summary
As the temperature drops I expect that avalanche activity will continue to 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 in the region, producing numerous avalanches up to size 3.5. Reactive wind slabs may be lingering in the alpine and could produce large avalanches where they sit above the surface hoar.
Snowpack Summary
In the north of the region up to 10 cm of new snow sits on a variety of old surfaces. A melt freeze crust can be found at or just below the surface up to around 2000m. I suspect that the crust is breakable at treeline and becomes thicker and more supportive at lower elevations. Strong southwesterly winds redistributed snow in the alpine forming windslabs in lee features. The mid-January surface hoar layer remains a concern and can be found down between 40 and 80 cm. I suspect that this layer may have been destroyed by moist/wet snow bellow treeline. The midpack is broken by the mid-December surface hoar layer 80 to 140cm below the surface. This layer appears to be slowly gaining strength.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.