Warming temperatures will increase the sensitivity of weaknesses in the snowpack, be particularly cautious midday - especially if the sun comes out.
Weather Forecast
Monday: Mainly cloudy. Flurries. Ridgetop winds moderate-strong West. Freezing level 1800m. Alpine temps High -1, Low -5Tuesday: Cloudy. Snowfall (4-6cm). Ridgetop winds light SW. Freezing level 2150m. Alpine temps High -1, Low -3.Wednesday: Mainly sunny. Ridgetop winds moderate-strong SW. Freezing level 2300m. Alpine temps High 0, Low -1
Snowpack Summary
Up to 20cm cm of snow since last week is settling rapidly due to a strong inversion (+4 at 1650m). Moderate SW winds have redistributed the new snow into Storm Slabs. While persistent weak layers in the mid and lower snowpack are relatively strong, near daily snowfall since February 25 means these layers are being increasingly stressed.
Avalanche Summary
Several small-large storm slab, cornice and loose snow avalanches occurred on Saturday as a result of ongoing snowfall, warm temps and wind. On Saturday night a large (size 3) slab avalanche occurred on a cross-loaded NW aspect, this is suspected to have failed on a deep persistent weak layer of facets, possibly combined with a crust.
Confidence
Freezing levels are uncertain
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.
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.