Regions
Kootenay Boundary.
Storm slabs continue to settle and gain strength but the deeply buried persistent weak layer remains a concern.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Thursday: Mostly cloudy with isolated flurries, light westerly winds, and freezing levels rising to around 1100m. Friday: Flurries starting with moderate southwest winds, freezing level near 1300m. Saturday: Cloudy periods with scattered flurries and moderate to strong southwest winds. Freezing levels remain around 1300m.
Avalanche Summary
No new avalanche observations from this region.
Snowpack Summary
A storm slab 30-40 cm deep can be found across most of the region. This new snow lies above a variable old surface buried at the end of January. This interface is being reported as a layer of surface hoar at treeline in the Rossland area. However, in most other parts of the region the new snow sits on a rain crust and/or old wind slabs. A weak layer buried mid-January can be found down 45-50cm, however, snow pit tests indicate that this layer is gaining strength. Deeper in the snowpack, the persistent weak layer that was buried earlier in January is now down 80-120 cm and continues to give sudden planar fractures in snowpack tests under moderate to heavy loads.
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.