Spring skiing is here. Early starts and early finishes are crucial to playing safe! Although supportive in the morning, the upper snowpack is moist and will breakdown quickly with daytime warming.
Weather Forecast
There'll be a shift in the weather pattern today with the upper ridge being pushed out by a cool upper trough. Today will be a mix of sun and cloud with little to no precip, ridgetop wind will be SW 20kph gusting to 60. Freezing level will rise to 2200m late morning and start to drop in the afternoon. Up to 8cm of snow is forecasted for tonight.
Snowpack Summary
We experienced a good freeze in the valley bottom overnight but a temp inversion kept the alpine temps above zero overnight. The clear windy night will have created a marginal surface crust but this will break down with daytime heating & sun. Recent winds have likely redistributed remaining dry snow in the alpine leaving variable wind slabs
Avalanche Summary
We have been experiencing regular natural avalanche cycles in the afternoon with daytime warming and the strong effects of the sun. Avalanches have been in the sz 1.5 - 2.5 range and either loose wet or wet slab releases. Sporadic glide crack releases to sz 3 have been witnessed every few days which are large, destructive & tricky to forecast
Problems
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.
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.