Regions
Kootenay Boundary.
Wind slabs may be reactive to rider triggering. The safest, best riding may be in lower elevation terrain sheltered from the wind.
Confidence
Moderate - Wind effect is extremely variable
Weather Forecast
The dominating arctic ridge is slowly breaking down as we transition to a more zonal (westerly) flow. Cloudy with some sunny periods, westerly winds and slightly warmer alpine temperatures will persist through the weekend. A more significant change to come early next week. Friday/ Saturday/ Sunday: Mix of sun and cloud with mostly cloudy skies on Saturday. Ridetop winds will be light from the SW-W and alpine temperatures near -9.
Avalanche Summary
On Wednesday, numerous natural loose dry and wind slab avalanches up to size 2 were reported. Most of these failed on solar aspects, or wind slabs that were triggered by people. With the winds recently switching directions, wind slabs should be expected on a variety of aspects.
Snowpack Summary
Up to 20 cm of recent snow has buried a plethora of old snow surface. This interface consists of wind scoured surfaces and old wind slabs, widespread near surface faceting (sugary snow), surface hoar in sheltered locations, and/or a breakable sun crust on steep solar aspects. Recent moderate to strong winds from all directions has redistributed some of this new snow into reactive wind slabs on a variety of aspects. Below this exists a couple of old freezing rain crusts from late-December, depending on your location. The mid-December surface hoar/ facet layer typically sits down 40-70 cm. This layer is still reactive to some snowpack tests in some areas but is currently considered to be dormant or inactive. Below this layer, the snowpack is generally well settled and stable.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.