Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain on Saturday
Weather Forecast
On saturday snow will continue with accumulations of 10-20cm, moderate to strong southwest winds and freezing levels climbing as high as 1800m. On sunday light flurries will continue through the morning, but a clearing trend is expected for the afternoon bringing light northwest winds and freezing levels at about 1000m. On monday expect light to moderate snowfall, increased westerly alpine winds and freezing levels at valley bottom.
Avalanche Summary
Recent observations include several easily triggered pockets of fresh wind slab in immediate lee terrain near ridge crests. The size and likelihood of avalanches should increase with saturday's forecast weather.
Snowpack Summary
Large surface hoar and faceted powder on sheltered shady slopes, and a surface crust on sun-exposed slopes, are now lightly buried in some locations and should continue to get buried over the forecast period. Assuming the structure of this current snow surface is preserved long enough for a sufficiently thick and cohesive slab to bury it, then a highly unstable situation should develop. Particularly where surface hoar and/or faceted crystals are associated with a weak crust. Generally speaking the longer surface snow is exposed to the elements before it gets burred, the more likely it is to become a serious problem. The mid and lower snowpack are generally well settled and strong, but faceted. Basal facets and depth hoar necessitate caution on wind-exposed slopes with highly variable snowpack depths, where this deep persistent weakness could be triggered from a shallow spot. Check out the Forecaster's Blog link below for more general snowpack discussion and good advice.
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.