Wind slabs sit above a weak mid-pack, creating the potential for small avalanches to step down to deeper layers.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
SATURDAY: Scattered flurries with 5-10 cm accumulations, light east winds, alpine temperature -10C.SUNDAY: Mix of sun and cloud, calm, alpine temperature -14C.MONDAY: Isolated flurries, moderate southwest winds, alpine temperatures -11C.
Avalanche Summary
Wind and storm slabs continue to be reactive to heavy explosive triggers, releasing size 2-2.5 avalanches on facets 60-100 cm deep. There is a bit of uncertainty regarding how last week's snow will bond to old surfaces that formed during the cold snap. Given this, there is still potential for skier and rider triggering in sheltered areas where buried surface hoar may exist, or in wind exposed terrain where wind slabs maybe sitting on facets.
Snowpack Summary
10-20 cm of new low density snow sits above 30-40 cm of settling storm snow from earlier this week. The storm snow sits above a variable surface that developed during the cold, dry, and windy conditions earlier this month and has been most reactive in wind-exposed terrain. The old interface consists of scoured surfaces and wind slabs in exposed terrain, weak faceted (sugary) snow, and surface hoar up to 20 mm in sheltered areas. In sheltered areas, you may find another layer of surface hoar and facets in the mid-pack that was buried around December 10. The thick crust from mid-November is near the bottom of the snowpack and reports suggest that the crust is currently well bonded to the surrounding snow.
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.