Strong winds and mild temperatures will continue to be the story for the next while. Unfortunately, this may leave us generally poor snow quality.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Saturday: Cloudy with a chance of flurries and sunny breaks. The freezing level is around 1200-1400 m during the day. Ridge winds are moderate to strong from the W-SW. Sunday: Cloudy with light snow overnight and flurries with sunny breaks during the day. The freezing level rises to 1500-1800 m and winds are strong from the SW. Monday: Cloudy with sunny breaks. The freezing level is 2000-2300 m and winds are moderate from the west.
Avalanche Summary
Loose wet activity has been reported throughout the week as a result of warm temperatures and sunshine.
Snowpack Summary
Moist new snow is probably sitting on a melt-freeze crust on southerly aspects and lower elevation terrain. Up higher, strong southwest winds have resulted in widespread wind effect in exposed terrain. Thick, stiff wind slabs can be found on north aspects in the alpine. Sheltered northerly aspects may still be hanging onto dry snow. Cornices have grown significantly. In some areas you may find a supportive crust down 30cm that extends up to around 1900m. A layer of buried surface hoar can be found between 40 and 60cm down and remains a concern west of the Continental Divide. The snowpack rests on a weak crust/facet layer from early December.
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.