Regions
Kootenay Boundary.
If more then 10 cm of new snow arrives on Sunday, the Alpine Hazard will rise to CONSIDERABLE.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain on Monday
Weather Forecast
The Interior will see generally dry, cool conditions under the current NW flow. A Pacific frontal system will arrive Sunday, bringing light- moderate amounts of precipitation and warmer temperatures.Sunday: Cloudy with snow amounts 6 cm. Alpine temperatures near -4. Light SW winds. Freezing levels near 1100 m. Monday: Snow amounts 10-20 cm. Alpine temperatures near -4. Moderate- strong NW westerly ridgetop winds. Freezing levels 1100 m.Tuesday: Cloudy with sunny periods. Alpine temperatures near -10. Ridgetop winds light from the West. Freezing levels near 500 m.
Avalanche Summary
Numerous loose dry natural sluffing up to size 1 from steeper terrain features. Small pockets of wind slab is easily rider triggered, and avalanche danger will likely rise through the forecast period with continued snowfall amounts and rising temperatures.
Snowpack Summary
Recent light snowfall and strong westerly winds formed pockets of soft wind slab on lee slopes and scoured windward slopes in exposed terrain. Loose dry surface sluffing is likely on most steeper slopes and terrain features.Buried between 35 - 50 cm below the surface you may find a weak layer of surface hoar on sheltered slopes or a melt-freeze crust/ facet combo on steep solar aspects. Most reports indicate this layer is "stubborn" to trigger, or there may not be a deep enough overlying slab to create a significant hazard. That said, I'd remain curious about this interface, especially as the snow load above gradually increases.In general, snowpack depths are below seasonal average and many slopes below treeline are reported to be below threshold for avalanche activity. Deeper snow is likely in the northern part of the region.
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.