Solar radiation will rapidly and dramatically increase the avalanche danger at all elevations if it occurs . Pay close attention to freezing levels.
Weather Forecast
Snow at the icefields over Sat and Sun, total 15cm. Winds Mod SW alpine highs -4. FzL 1,800m
Snowpack Summary
Temp surface crusts below 1,700m on all aspects, extending to treeline on Solar facing slopes. Below the crust at lower elevations the snowpack is turning isothermal. Thin soft wind slabs at ridge features which stiffen and thicken with elevation. The midpack is consolidated and providing bridging strength over a weak and faceted snowpack base.
Avalanche Summary
Several slab avalanches size 2-3 from steep easterly facing alpine terrain. These were likely triggered by cornice failures and stepped down to basal layers running into the valley bottom. Explosive work at lower elevations produced several class 2 moist snow avalanches.
Confidence
Freezing levels are uncertain on Sunday
Problems
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.
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.
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.