Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Friday: moderate precipitation starting Thursday evening and continuing throughout Friday morning / moderate southeasterly winds / freezing level at 1600m Saturday: cloudy skies with light snowfall / light and variable winds / freezing level at 1600m Sunday: overcast skies with a possibility of clearing in the afternoon / light to moderate easterly winds / freezing level at 1700m
Avalanche Summary
No new avalanches were reported from the region on Wednesday: however, observations were extremely limited. I suspect that there was continued natural wet avalanche activity in response to very warm temperatures and intermittent direct solar radiation. With the current weather pattern, I expect a shift from wet snow avalanches to storm snow instabilities at higher elevations, while wet snow instabilities will still exist below treeline.
Snowpack Summary
Very warm temperatures have dominated the region in recent days and all but the highest, north-facing slopes saw moist to wet surface conditions. As of Thursday morning, slightly cooler temperatures have allowed light amounts of new snow to fall above about 2000m while rain continued to penetrate and weaken the snowpack at lower elevations. Up to 60cm below the surface, you might find a weak crust interface in the alpine and at treeline; however, I suspect that forecast cooling may assist in strengthening this weak layer in most areas. The mid-February buried surface hoar layer is down about 200 cm, although avalanches releasing on this layer represent a very low probability-high consequence scenario. Cornices in the region are very large. With spring temperatures, these are more likely to become weak and fail. They could provide a large enough trigger to release deep layers on slopes below.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.