Winds have raked the landscape and not much left for winds to move. Good skiing is hard to find. If freezing levels are higher than forecasted for Monday, the danger rating may rise correspondingly.
Weather Forecast
Sunday: ridgetop winds NW 40km/hr, surface freezing level with light snow. Monday: NW 75km/hr, 1900m freezing level, no snow and cloudy periods but mainly sun. Tuesday: SW 25km/hr, afternoon freezing level 1400m and no snow.
Snowpack Summary
Extreme NW winds have stripped alpine and tree line fetch zones. Hard wind slabs are present on treeline and above lee slopes. Buried surface hoar is found at some locations 10-40cm down depending on windloading patterns. Weak basal facets dominate thin areas. Below tree line, the old storm snow is moist over rotten facets.
Avalanche Summary
On Friday, in the Whistler's area, numerous full depth natural slab avalanches occurred on thin, steep, lee alpine slopes. In the days preceding, we were seeing up to size 3 from wind loading. They were running far in paths with steep run outs. Saturday's patrol no new avalanches were observed on hy 93 as slightly cooler temps helped to stabilize.
Confidence
Freezing levels are uncertain 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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.