Triggering an avalanche remains a concern at all elevations. Be very suspect around wind-affected slopes and convex terrain features.
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
TUESDAY: Sunny, light north wind, alpine high temperatures around -10 C.WEDNESDAY: Mix of sun and cloud with isolated flurries, moderate north wind, alpine high temperatures around -7 C. THURSDAY: Mostly sunny, moderate north wind, alpine high temperatures around -5 C.
Avalanche Summary
No new avalanches were reported on Sunday, but whumpfing in flat terrain (a sign of instability) was reported in the North Shore mountains. Storm snow was very reactive on Saturday. There were numerous size 1-2 slab avalanches triggered by skiers on all aspects at treeline and below treeline elevations, including some that were triggered remotely (from a distance).Looking ahead, avalanche activity is most likely in areas that have been loaded by the recent northerly winds, but any steep terrain feature is suspect given the widespread crust sitting beneath the storm snow.
Snowpack Summary
In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, cold weather is preserving 30-50 cm of low density snow. A hard rain crust that extends into alpine terrain is buried about 40 cm beneath the recent storm snow. Reports suggest the snow has a poor bond to the crust, meaning there's a potential for slab avalanches on any steep or convex terrain feature. Monitor the bond of the snow to this crust closely. There are no significant layers of concern below the crust.
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.
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.
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.