Watch for lingering wind slabs in high north facing terrain and loose sluffing on steep sun exposed slopes.
Weather Forecast
Lingering flurries are possible Wednesday morning and sunny conditions are expected Wednesday afternoon. Alpine wind is expected to be light from the west and treeline temperatures are forecast to be around -10C. Similar conditions are expected for Thursday and Friday with mostly sunny skies, light alpine wind, and treeline temperatures remaining around -10C.
Avalanche Summary
On Monday, natural sluffing was observed from steep sun exposed slopes. Skiers and explosives triggered a few storm slabs and wind slabs size 1-1.5. These slabs were typically 20-40 cm thick and one wind slab was up to 60 cm thick. On Sunday, avalanche activity was limited to ski cutting producing a few size 1 soft slabs which were 10-15 cm thick and isolated to the most recent storm snow. On Wednesday, lingering wind slabs are the main concern. Look for these in immediately leeward features on northerly aspects in exposed terrain. Sluffing from steep sun exposed slopes is also possible during the heat of the afternoon.
Snowpack Summary
At higher elevations, the widespread mid-February melt-freeze crust is now typically down 20-40 cm. This crust extends as high as 2200 m and is up to 15 cm thick at treeline. The recent storm snow is reported to be bonding well to the crust. Reports from Monday suggests the recent storm snow is now faceting with the current cold temperatures and new surface hoar is forming. In the alpine, wind slabs and cornices were previously being reported on high northerly aspects but these are expected to have gained considerable strength over the past couple days of cold temperatures. Below 1150 m, the snow surface was reported to be wet on Monday.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.