Sunshine on Wednesday will play a major role in natural avalanches on S'ly aspects.
Expect avalanche activity to follow the arc of the sun, peaking when direct sun bakes the slopes.
Moderate to strong SW winds are redistributing the new snow into Alpine and Treeline lee features. Be suspect of slopes where stiffer, dense surface slabs are present; these slabs are ripe for human triggering.
New storm snow (70cm in the west, 50cm in the east) overlies a firm crust at treeline and above. Direct observations and reports from nearest neighbours indicate a poor bond to the underlying bed surface.
Clearing Wed, then a dramatic warming Thurs with sun and cloud to mimic the greenhouse effect.
Tonight: Clearing, trace to 5cm, Alp low -10*C, FZL 500m, gusty mod W winds
Wed: Sun and cloud, Alp high -5*C, FZL 1500m, light SW winds
Thurs: Sun and cloud, Alp high 2*C, FZL 2800m, mod SW winds
Fri: Flurries, 6cm, Alp high 1*C, FZL 2100m, strong SW winds
50-70cm of snow in the last 4 days at Treeline and above has buried a variety of surfaces (wind slabs, solar crusts to mtn top, and a melt/freeze crust to 2200m). Slopes in the Alpine hold cold, wintery snow, deeper on N'ly aspects. The December 1st crust is down 1.5-2m. Late season cornices are LARGE, with fresh, fragile new lobes recently added.
A field team in the west end of the park easily ski cut a sz 2 persistent slab, 70cm deep, 50m wide, NE aspect, at 2150m.
Artillery control on Mon produced slab avalanches up to sz 3-3.5, N aspects being most reactive to explosives.
Nearest neighbours report easy triggering of the new wind/persistent slab between 2000-2200m on slopes >35*.
