Regions
Kootenay Boundary.
Don't be fooled by the Moderate danger ratings. Buried weak layers still exist and may surprise in isolated terrain with nasty consequences.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
Wednesday: 3-5cm of new snow / Moderate westerly winds / Alpine temperature of about -15Thursday: 3-5cm of new snow / Light southerly winds / Alpine temperature of about -8Friday: 5-15cm of new snow / Light southerly winds / Alpine temperature of about -7
Avalanche Summary
No new avalanches have been reported. As new snow accumulates over the next few days, storm slabs should be on your radar. More importantly, the December 15th interface will become deeper and the overlying slab will likely settle and gain cohesion increasing the likelihood and destructive potential of this buried persistent weak layer.
Snowpack Summary
Last week's storm snow has now settled into a 30-80 cm soft slab. This slab overlies the December 15th interface which consists of a melt-freeze crust on steep, solar, higher elevation slopes and well-developed surface hoar everywhere else which seems most pronounced in sheltered treeline terrain and below. The bond at this variable interface is of critical importance, especially in areas where the overlying slab is deep and well-consolidated.The late November crust is now buried 60-100 cm and has been producing hard, resistant results in recent snowpack tests. Beneath this crust the lower snowpack is strong and well-settled.
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.
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.