Spring conditions. Avalanche danger is expected to rise during the day with warming and solar radiation. Plan to retreat to cooler north-facing terrain if the snow surface is becoming moist or wet.
Weather Forecast
SATURDAY: A mix of sun and cloud. The freezing level could drop to 1700 m overnight before rising to around 2200 m during the day. Northwesterly winds peak overnight and ease to light northerly during the day. SUNDAY: Mainly sunny. The freezing level shoots up again to 2400 m and winds are light and variable. MONDAY: A mix of sun and cloud. The freezing level remains near 2500 m and winds are light.
Avalanche Summary
Some loose wet activity to size 2 and isolated cornice falls were reported on Thursday and Friday. The possibility of persistent slabs and cornice falls should increase if the snowpack does not refreeze overnight and temperatures remain high.
Snowpack Summary
The snow surface is currently going through a typical spring melt-freeze cycle on all aspects and at all elevations, except possibly high true-north slopes which could be holding onto cold snow. A moist/wet, isothermal, and rapidly melting snowpack exists on all aspects below around 1500 m and probably even higher on solar aspects. The strength (thickness) of the surface crust and how quickly it breaks down during the day are important factors to focus on. The late February persistent weak layer is down 80 to 120 cm below the surface. This layer may be a concern in isolated terrain, but it will probably take a large trigger like a cornice fall or surface avalanche in motion to set it off.
Problems
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.
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.