Avalanche control is planned for HWY 742 between 10:30 and 14:30. Expect delays.
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
Up to 20cm of new snow is possible over the next 12 hours, with rain at lower elevations until temperatures cool late this evening. Sunday will be a mix of sun and cloud with much cooler temperatures and westerly winds gusting to 65 km/h.
Avalanche Summary
Visibility was very limited today. An avalanche cycle continues, with recent slab avalanches up to size 3.5 occurring on all aspects at all elevations. All of the avalanches are stepping down to the basal weak layers. Crowns are up to 1.5m deep and propagations have been wide. Many avalanches have reached or exceeded their historic run-outs, in some cases destroying significant tracts of mature forest.
Snowpack Summary
Rain fell through the day up to an elevation of 2200m. The snowpack is isothermal at lower elevations. Wind slabs are present in Alpine and Treeline areas on all aspects but localized additional loading has been noted on lee features. Cornices are large and sagging. Extensive avalanche activity has occurred over the last few days, that has all stepped down to the basal weaknesses resulting in large destructive avalanches.
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.
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.