Confidence
Fair - Due to limited field observations on Monday
Weather Forecast
Precipitation is expected to increase during the day on Sunday with about 3-5 mm forecast by Monday morning. Winds are expected to increase to moderate from the southwest, and the freezing level is expected to rise to about 2300 metres on Sunday and drop to 2000 metres by Monday morning.
Avalanche Summary
Natural moist and wet loose snow avalanches were reported from Friday up to size 2.0, some wet slab avalanches were also reported. Moist and wet loose avalanches continued to release on Saturday from solar exposed aspects.
Snowpack Summary
On Thursday, moderate to locally heavy accumulations formed wind slabs at treeline and above on a variety of temperature-affected surfaces that include well settled powder, wet grains and crust sandwiches. Rain has continued to penetrate and weaken the isothermal snowpack at lower elevations. The mid-February buried surface hoar layer is down about 140-220 cm, although avalanches releasing on this layer represent an extremely low probability-high consequence scenario. Cornices in the region are very large. With spring temperatures, and direct solar radiation these are more likely to become weak and fail. They could provide a large enough trigger to release deep layers on slopes below. Average snowpack depth in the alpine remains in the 3 m range.
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.
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.