Ongoing snowfall and southerly winds will continue to load to already thick storm slabs and large cornices. Conservative terrain selection is recommended.
Confidence
Moderate - Wind speed and direction is uncertain on Tuesday
Weather Forecast
MONDAY: moderate to light snow starting overnight with 5-20cm expected by the end of the day, mainly light westerly winds, 1200m freezing level. TUESDAY: light snowfall continues, light westerly winds, 1200m freezing level. WEDNESDAY: clearing, light and variable winds, 1200m freezing level.
Avalanche Summary
Natural and artificially triggered avalanche activity up to size 2.5 was reported from across the region on Saturday. Cornices remain large and fragile. They have been failing naturally and would likely collapse under the weight of a person.
Snowpack Summary
Up to 75cm of recent storm snow is being reported in sheltered areas with up to 150cm in wind loaded areas. Weaknesses within or at the base of the new storm snow may need a couple days to settle and strengthen. Southerly winds have created very deep and dense slabs in lee terrain, probably well below ridge crests, while scouring windward slopes. Cornices are large and fragile. The mid and lower snowpack are strong and 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.