Touchy wind slabs are sensitive to human triggering in the Alpine. Down in the valley, warm overnight temps means the surface crust will break down quickly and hazard will rise as a result.
Weather Forecast
Mainly cloudy today, with 2-5 cm forecast in the alpine and potential for rain showers late in the afternoon at lower elevations. Ridge top wind will be from the SW at 10-25kph with freezing levels rising to 1800m. Tuesday will remain unsettled with some snowfall and freezing levels hovering around 1800m, this weather pattern continues to Thursday.
Snowpack Summary
10-20cm of new snow in the last 48 hrs. Moderate SW winds at tree-line and alpine have formed wind slabs on lee features & huge cornices at ridgetop. These slabs sit on a temp crust that extends to ridgetop. Cold, dry snow can be found on high northerly slopes while solar aspects become moist with sunshine & isothermal snow can be found below TL.
Avalanche Summary
A field team encountered touchy surface wind slabs in northerly lee aspects at 2200m. The 10-15cm soft slabs were easily failing with ski cuts and running fast on a temp crust. This layer was observed to be still reactive yesterday in the Asulkan valley. Late last week avalanches to size 3.5 were observed, likely cornice triggered.
Confidence
Freezing levels are uncertain
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.
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.