When the snow first turns to rain a widespread natural avalanche cycle will likely ensue for a short period of time.
Weather Forecast
Wednesday night: 25-30 mm water / Strong, southwesterly winds/ Freezing level rising to 2000 m by Thursday morning.Thursday: 35-40 mm rain / Strong to extreme, southwesterly winds / Freezing level around 2000 m.Friday: 10-15 mm rain / Moderate to strong, southwesterly winds / Freezing level dropping to around 800 m.Saturday: Mostly cloudy / Moderate, southwesterly winds/ Freezing level around 800 m.
Avalanche Summary
The rain on snow event that is forecast for early Thursday morning is expected to trigger a widespread natural avalanche cycle for a short period of time at treeline and below. In the alpine, where the precipitation is forecast to fall as snow, danger is expected to remain High throughout the day.
Snowpack Summary
50-80 cm of recent storm snow is sitting on a knife hard crust. The bond to this crust is slowly gaining strength according to recent reports. The mid and lower snowpack are settled and well bonded with the average snowpack depth at treeline 250-300 cm.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.
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.