Use extra caution on open leeward slopes at treeline and in the alpine. New wind slabs are are lurking and could be touchy to rider triggers.
Weather Forecast
The Pacific low continues to intensify off the coast bringing precipitation and strong winds to the Interior regions. The surface low sitting east of the Rockies will drive unsettled conditions bringing continued snow and wind Sunday and Monday.Friday: Cloudy, freezing levels valley bottom, snow amounts 2-8 cm, ridgetop winds strong from the southwest.Saturday: Cloudy freezing levels valley bottom, snow amounts 5-10 cm, ridgetop winds moderate-strong from the West.Sunday: Some model disagreement. Unsettled conditions may bring snow amounts 5-10 cm with moderate to gusting winds from the northwest.
Avalanche Summary
No new avalanche reports from this region. On November 28th several size 1.5 wind slabs were reported on the MIN (Mountain Information Network)
Snowpack Summary
New snow and strong winds will likely build wind slabs on open leeward slopes and behind terrain features. Early season snowpack observations are still very limited but the threshold for avalanches has been exceeded at treeline and in the alpine. Reports suggest that the snow depth at treeline is typically 110-150 cm but a report from the east side of region shows only 80 cm at treeline. The snowpack tapers off drastically below treeline and below 1700 m there is not yet enough snow for avalanches. Limited reports suggest the crust from the middle of November is down 50-80 cm and the crust from early November is down 80-110 cm.
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.