Large skier triggered avalanches are still possible after last week's storm. Steep solar aspects appear to be most reactive, and prudent route selection is advised in all locations. Be aware of the effects of solar radiation and cornice failures.
Weather Forecast
A weak upper ridge lingers over the area today, bringing occasional sunny breaks and rising freezing levels. Another low pressure is expected to move in on Wednesday, with moderate SW winds and moderate precipitation (up to 10 cm). Another ridge is expected for Thursday.
Snowpack Summary
60+ cm of storm snow overlies a variety of old surfaces. Although the storm snow is settling, it is still failing as a cohesive slab, especially on solar aspects where it sits on a sun crust. The Feb 12 PWL is down over one meter, and remains a concern. This layer can still be triggered by heavy loads, or as a step-down from storm snow releases.
Avalanche Summary
Natural avalanche activity has tapered off, but human triggered avalanches remain likely in specific terrain. Yesterday, skiers triggered a size 3 avalanche on a west aspect in the alpine. It failed less than a meter from their skis, and propagated 150 m wide, running to valley bottom. It likely ran on a sun crust interface.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Wednesday
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.