Moderate - Forecast snowfall amounts are uncertain on Tuesday
SUNDAY NIGHT: Clear periods. Alpine temperatures near -18C. Ridgetop winds light from the south.MONDAY: Mix of sun and cloud with isolated flurries, trace accumulation. Alpine temperatures near -15C. Ridgetop winds light from the south.TUESDAY: Cloudy with scattered flurries, 5-10 cm accumulation. Alpine temperatures near -10C. Ridgetop winds moderate from the south.WEDNESDAY: Cloudy with scattered flurries, 5-10 cm accumulation. Alpine temperatures near -8C. Ridgetop winds light to moderate from the southeast.TUESDAY: Broken cloud cover, freezing level at valley bottom, around -20 C in the alpine, light variable wind at most elevations with moderate to strong southwest wind at ridgetop, a few centimeters of snow possible.
Strong to extreme wind Friday night into Saturday initiated a natural wind slab avalanche cycle. Wind slab avalanches to size 2.5 were reported on all aspects and occurring above 2000 m. Check out this MCR report
of a skier triggered wind slab from an east facing aspect at 2370 m in the adjacent Glacier National Park region on Saturday.A persistent weak layer that was buried in mid-January continues to be reactive to human triggers. This layer is sensitive enough for avalanches to trigger remotely (from a distance). Activity on this interface continued through Friday as skiers triggered avalanches to size 1.5 on north through northeast facing terrain between 1650 and 1900 m. At higher elevations (2000-2300 m) small wind slabs were reactive to skier traffic on all aspects including a size 2 skier triggered avalanche on a west aspect while skiing over a roll.Human triggered avalanches size 1.5 to 2.5 were widespread last week on a variety of aspects at treeline and below.
20-70 cm of recent new snow sits on wind slab, surface hoar (feathery crystals), facets (sugary snow) and a crust on sun-exposed slopes. In many areas, recent winds have formed wind slabs on all aspects due to shifting wind directions. The most notable feature in the snowpack at this time is a persistent weak layer that was buried in mid January, which is now buried 40-90cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer is the most prominent at treeline and below, and continues to produce avalanches.