Watch out for reactive pockets of soft slab in wind loaded features or on steep unsupported slopes.
Confidence
Moderate - Track of incoming weather systems is uncertain on Tuesday
Weather Forecast
MONDAY: up to 5cm of new snow overnight with isolated flurries continuing through the day, light variable winds, 1500m freezing level. TUESDAY: light to moderate snowfall through the day with accumulations of up to 10cm expected, moderate southerly winds, 1800m freezing level. WEDNESDAY: snowfall continuing overnight with up to 10cm expected before a clearing trend through the day, light westerly winds, freezing level of 1900m.
Avalanche Summary
Isolated artificially and naturally triggered storm slab, wind slab and cornice avalanches continue to be reported. Cornices are large and fragile, and may fail under the weight of a person.
Snowpack Summary
Cornices are large and weak. The new snow may sit above crust and or moist snow that was reported on all aspects and elevations although some high north facing features may have stayed cool. In wind loaded features, soft slabs may be reactive to human triggers. The mid-pack is generally well settled. A layer of surface hoar buried in early January can be found down 1-2 m. In most places it is thought to be capped by a thick widespread crust although it has produced some recent isolated hard sudden planar snowpit test failures in thinner snowpack areas.
Problems
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.
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.