The primary avalanche concerns are wind slabs in exposed terrain and cornices along ridgelines.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Thursday: 2-4 cm new snow. Freezing level around 600 m. Moderate easterly winds.Friday: Flurries. Freezing level around 600 m. Light southeasterly winds.Saturday: Around 5 cm new snow. Freezing level around 700 m. Light easterly winds.
Avalanche Summary
On Tuesday, small avalanches were observed in the Alexander Creek area. On Monday, small natural avalanches were reported from the region, and ski cutting produced similar small avalanches on wind-loaded features. Also on Monday, explosives triggered one size 2 wind slab avalanche on an east aspect at 2300 m. This avalanche ran on a 60 cm deep crust layer.
Snowpack Summary
10-30 cm of snow sits above a variety of crusts on all but high north aspects. Northern parts of the region have less new snow than southern parts. Wind has formed hard slabs in lee features, and in some cases the snow may be poorly bonded to the crusts.Multiple crusts exist in the top metre of the snowpack. Some parts of the region may have a surface hoar layer roughly 60 cm deep on north aspects at treeline.A well settled midpack sits above sugary facets in many parts of the region, especially thin snowpack areas.
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.