Regions
Northwest Coastal.
Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
Monday: light to moderate snowfall continuing overnight - strong to extreme southeast winds - freezing level at 800m Tuesday: light snowfall - strong southeasterly winds - freezing level at 700m Wednesday: moderate to heavy snowfall starting tuesday evening - strong southwest winds - freezing level at 700m
Avalanche Summary
On Saturday sluffing to size 2 was observed in steep, sun-exposed terrain. There has also been an increase in glide crack activity on solar aspects, especially where rocky ground cover is smooth and slabby. I expect a spike in wind slab avalanche activity with forecast weather on Monday.
Snowpack Summary
Light amounts of recently fallen snow override a variety of old surfaces that include wind slab, crusts and spotty surface hoar. Spring-like conditions have existed over the past several days forming crusts on solar aspects at all elevations that become moist under sunny skies during the day. Melt conditions exist on all aspects below 1000 m, with no significant re-freeze. Below all this, down 60-120 cm exists a very spotty surface hoar/ facet interface. Operations from the field noted no recent activity on this layer. I suspect it's becoming dormant, but would be suspicious of large triggers like cornice fall, or under the weight of a sled and it's rider in specific areas. Cornices in the region are reported to be very large and potentially unstable.
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.