Be wary of any slopes receiving direct sun. Solar warming could trigger avalanches or weaken existing slabs.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
Thursday: Light snow. 5-10cm. Light to moderate south-west winds. Freezing level valley floor.Friday/Saturday: Clear and sunny. Light winds. Afternoon temperatures rising on sunny slopes, with the freezing level falling to valley floor at night.
Avalanche Summary
In the Dogtooth Range on Tuesday, a size 3 slab was triggered by a skier on a north aspect. It's suspected to have initiated on the February weakness, and stepped to ground. Two large slabs (size 2-2.5) also released naturally on north to north-east aspects, up to 1 m deep. There were two snowmobile-triggered size 3 avalanches in the southern Purcells near Kimberley (read more in 'related incidents'on this page). I'm concerned about strong solar warming on Friday and Saturday potentially triggering cornice fall or surface avalanches, which could step down to persistent weaknesses and create very large avalanches.
Snowpack Summary
Newly formed soft wind slabs were touchy on Wednesday in specific terrain. Deeper in the snowpack, the major concerns are the mid-February persistent weak layer, buried 1-2 m deep, and facets at the base of the snowpack. Neither of these has truly healed and sporadic very large avalanches continue to occur.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.