Avalanche danger is expected to increase over the weekend.
Confidence
Fair - Intensity of incoming weather is uncertainfor the entire period
Weather Forecast
Friday: Light snowfall in the morning with 2-5cm expected. Freezing levels around 1200m and moderate southwesterly winds before precipitation picks up, winds increase and freeing levels rise in the evening. Saturday: Another 20-30cm late in the day is expected to add to the 15-25cm of new snow already on the ground. Freezing levels as high as 1700m and strong westerly winds. Sunday: Continued moderate snowfall and moderate to strong southwesterly winds, with freeing levels back around 1200m.
Avalanche Summary
Recent observations are limited to isolated human-triggered Size 1 fresh wind slabs. One was 20m wide by 20cm deep on a NE facing alpine slope.
Snowpack Summary
Alpine areas are wind-hammered with scoured and pressed surfaces, exposed crusts, and pockets of hard and soft wind slabs. Buried surface hoar and/or facets persists 10-20cm below a weak rain crust on sheltered treeline slopes and below. Recent compression tests on a treeline slope produced easy to moderate sudden collapse results down 65cm on on this weakness where it was wind-loaded. Watch this layer as it gets more load and a thick cohesive slab develops, particularly below treeline where the buried surface hoar is especially large. A strong mid pack overlies weak basal facets and depth hoar in shallow alpine areas. This deep persistent weakness may also deserve attention with more load.
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.