A cooling trend is helping to lower avalanche danger but have also brought a return to more wintery problems at higher elevations. New snow, sustained winds, and persistent weak layers mean that there are lots of factors to keep in mind to stay safe.
Weather Forecast
Today will remain unsettled with convective flurries and potentially some sunny breaks. Moderate, but gusting to strong, westerly winds will be transporting the new snow building cornices and loading lee slopes. Thursday should be dry with a mix of sun and cloud. Alpine temps will reach -4'C. On Friday expect flurries and SW winds.
Snowpack Summary
Temps cooled off overnight, and at 1300m 3cm of snow overlies a 3cm thick crust. At 1900m ~20cm of dry snow overlies 30cm of heavy wet snow at treeline. This adds to the load sitting on a series of crust layers. Snowpack tests indicate that these layers may be triggerable by light loads, and if triggered are capable of propagating widely.
Avalanche Summary
Numerous size 2-3, loose wet avalanches were observed along the highway corridor. Avalanche activity tapered off in the afternoon as temps cooled, precipitation rates decreased and winds died down.
Confidence
Timing or intensity of solar radiation is uncertain
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.