Storm snow amounts are uncertain. The new snow may bond poorly to underlying crust surfaces. If more than 30 cm new snow arrives, consider the avalanche danger to be HIGH.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Tuesday: 15-20 cm new snow with freezing levels around 1200 m. Winds strong southerly in the morning, diminishing to light westerly in the afternoon.Wednesday: 5-10 cm or so new snow with freezing levels around 1200 m. Winds moderate to strong southwesterly.Thursday: 10-20 cm new snow. Freezing levels around 1200 m. Strong southerly winds.
Avalanche Summary
Natural avalanches were reported up to size 2.5 on Sunday. Activity diminished on Monday following a drying and cooling trend, but is likely to pick up again, especially in steep, wind affected terrain for Tuesday.
Snowpack Summary
Recent rain soaked the upper snowpack at all elevations before depositing roughly 5-10 cm of heavily wind affected new snow at higher elevations. In areas where extreme south winds have not scoured it away, approximately 20-30 cm of recent snow overlies the November 23 crust. This 5-10 cm thick crust can be found on all aspects above 1400 m, is present at the surface in windward areas, and overlies a generally rain-saturated snowpack. In high alpine and glaciated terrain a layer of weak sugary crystals that was buried on November 9th exists above a crust near the base of the snowpack. This interface is now buried 150-240 cm deep.
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.