Winds will be cranking through the weekend! New wind slabs may be easily triggered by a skier or snowmobiler.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The dominating Arctic high slides south allowing a series of Pacific frontal systems to cross the Interior through the forecast period. Strong ridgetop winds will crank up Saturday accompanied by new snow and slightly warmer temperatures Sunday and onward.Saturday: Alpine temperatures -13, ridgetop winds from the West 30-60 km/hr, snow 3-10 cm. Sunday: Alpine temperatures -11, ridgetop winds SW 50-60 km/h, snow 10-20 cm.Monday: Alpine temperatures -10, ridgetop winds SW 40-70 km/h, snow 15-20 cm.
Avalanche Summary
No new avalanche reports from Thursday. A large cornice fall up to size 2 was reported on Wednesday from a NE slope at 2400 m. The cornice fall did not trigger an avalanche from the slopes below but shows that they are becoming brittle. Loose dry sluffing could potentially push you around or off your line, so watch terrain traps below. With forecast strong winds, new wind slab problems may be triggered by light loads (skiers, sledders) over the weekend.
Snowpack Summary
Continued cold temperatures are promoting surface faceting at all elevations. Surfaces are reported to be wind-affected in exposed areas well into treeline. Wind slabs exist in lee terrain at treeline and in the alpine. Areas sheltered from the wind may be developing a new surface hoar layer. The mid-November crust is buried down 100-180 cm and produces variable results in snowpack tests. Moderate results may be more likely in shallower snowpack areas, and deeper snowpack areas may be more likely to show no results on this layer. Professionals continue to monitor the crust for facet development that may provide a weak layer above a hard sliding surface in the future.
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.