Expect new snow and strong winds to form wind slabs and grow fragile cornices. Cracking around skis and sleds are signs that the new snow is bonding poorly to the old surface. Avoid wind loaded areas with pillowy or chalky looking snow.
Confidence
Moderate - Wind effect is extremely variable
Weather Forecast
Monday: Mix of sun and cloud / Moderate to strong westerly winds / Alpine temperature of -16Tuesday: Light flurries / Moderate to strong westerly winds / Alpine temperature of -12Wednesday: Light flurries / Light and variable winds / Alpine temperature of -13
Avalanche Summary
No new avalanches were reported on Friday, although smaller human-triggered wind slab avalanches should be expected in exposed higher elevation terrain.Although deeper, persistent avalanche activity has become less frequent over the past week, light triggers in shallow rocky areas, as well as large triggers such as a cornice collapse or step down from a wind slab release, still have the potential to result in large destructive avalanches.
Snowpack Summary
Light amounts of new snow now cover storm snow totals from last week that range from15-30 cm, with closer to 50 cm in the very south of the region near Kimberley. Winds have redistributed these accumulations into deeper, reactive slabs in wind-exposed terrain. These accumulations sit on an interface that was buried mid-February consisting of; a mix of older wind slabs in exposed higher elevation terrain, a sun crust on steep solar aspects, and surface hoar on sheltered slopes. Several recent avalanches have failed on this layer in the past week.Within the mid and lower snowpack are several persistent weak layers that are beginning to show signs of improving but still remain suspect. Two surface hoar/ crust layers buried in January are now 80-120 cm below the snow surface. At least one of these layers can be found on all aspects and elevations.Deeper in the snowpack ( about 150 cm deep) is a facet/crust/surface hoar layer buried in December that is most prevalent at treeline elevations and below.Near the base of the snowpack is a crust/facet combo layer buried in late November.
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.
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.