As stormy weather tapers-off and a dry ridge gradually builds over the province, solar radiation will become the driver for natural avalanche activity.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Wednesday
Weather Forecast
On Tuesday night and Wednesday morning, expect a mix of sun and cloud with isolated spring "power flurries". Clouds should scatter by mid-day on Wednesday while Thursday and Friday will be mainly clear. Ridgetop winds will be light to moderate from the northwest on Wednesday, becoming generally calm on Thursday and Friday. Daytime freezing levels should sit at about 1200m for the forecast period.
Avalanche Summary
On Sunday, natural and human triggered wind slab activity to size 1.5 was observed on a variety of aspects at treeline and in the alpine. The avalanches formed in response to new snow and wind on Saturday. In one case, a smaller surface avalanche stepped down and triggered a size 3 slab on a southwest facing slope at treeline. It is unknown what interface the larger slab failed on. As stormy weather tapers-off and a dry ridge gradually builds over the province, solar radiation may become the driver for natural avalanche activity.
Snowpack Summary
At treeline and in the alpine you're likely to find wind slabs which formed during Saturday's stormy weather. 50-100cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layer seems variably reactive. In other words, it's still really touchy in some places while in other spots it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. I'd continue to be suspicious of steep, unsupported features at treeline and in the alpine as this layer has the potential for very large avalanches. Below this interface, the snowpack is generally gaining strength. At ridgetop, cornices are huge and potentially unstable.
Problems
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.