Reactive soft slabs can be found in wind loaded areas and steep unsupported slopes.
Confidence
Moderate - Wind speed and direction is uncertain on Monday
Weather Forecast
MONDAY: up to 10cm of snow overnight with isolated flurries through the day, light and variable winds, 1200m freezing level. TUESDAY: light snow overnight becoming heavy through the day with accumulations of 20-30cm expected, moderate southerly winds 1500m freezing level. WEDNESDAY: lingering flurries, light westerly winds, 1500m freezing level.
Avalanche Summary
A couple of new size 1-2 wind slabs were triggered naturally and by skiers over the weekend. A natural avalanche cycle is expected to have occurred through the storm on Sunday. Cornices are still large and fragile; they have been reported to be failing naturally and would likely collapse under the weight of a person.
Snowpack Summary
Moderate snowfall and winds have formed fresh soft slabs in the alpine and at treeline. The new snow sits on a crust at treeline and below as well as up to an elevation of about 2200m on aspects that see direct sun. Cornices are large and weak. The midpack is generally well settled.
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.