Cornices have been active in the past 72 hours, and careful attention is needed when traveling on or below corniced ridges.
Weather Forecast
Temps forecasted to drop to -20C by Saturday AM, then warming back up to -10C by the evening. Precipitation amounts are uncertain, with variability in the models, but up to 15cm of new snow possible in the next 24 hours. Winds will increase to moderate SW overnight, then expected to be variable throughout the weekend.
Snowpack Summary
Recent warm temperatures and rain followed by cooler temps have produced a widespread crust up to 2400m on all aspects. Above this, previous wind affected surfaces in exposed areas and wind slabs on lee aspects. We received 5-10cm of new snow today with minimal wind below treeline, but gusting to 50km/h in the alpine and loading North East aspects.
Avalanche Summary
Poor visibility today. Touchy cornices have been observed and reported in the past 48 hours. Some cornice falls triggered slabs up to size 2 at the ski hill during recent natural cornice failures.
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.
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.