Solar heating will continue to be the main variable affecting the snowpack for the next few days. Wind effect and crusts have created difficult downhill conditions on all but wind sheltered and shaded slopes. Hazard is low likelihood high consequence
Weather Forecast
Generally warm temperatures with freezing levels near 1500m through Thursday then rising towards 2300m Friday. Very dry conditions will persist with some thin cloud. A weak front slips down form the North on Wed which could bring minor amounts of precip and a lull in the steady moderate West winds . Very little snow remains available for transport.
Snowpack Summary
Warm temperatures and sun have created variable crusts on SE through SW slopes. West winds have stripped snow from any exposed features and created hard windslabs behind. 30 to 40 cm above the ground weak, facetted snow remains a concern on steep or unsupported planar slopes and in the many thin areas found with this highly variable snowpack.
Avalanche Summary
There has been very little avalanche activity observed in the Park in the last week however avalanches associated with the deep persistent slab have been triggered by a few parties in the neighboring regions. Although avalanche activity may decline in this stable period, remember that this problem will be with us for some time to come
Problems
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.
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.