Extra caution is still needed if traveling on or below sunny slopes. The sun's heat beating down on these slopes will elevate danger levels.
Weather Forecast
One more day of sun and the region moves back into a stormy trend. Today brings sun with increasing cloud late in the day. Freezing levels rise to 1800m and winds remain light SW. Tonight and tomorrow bring flurries, amounting to 5cm, freezing levels dropping to 1100m, and winds increasing to moderate SW. Sunday shows continued flurries.
Snowpack Summary
The sun has formed a breakable crust on SE through W aspects to near ridge-top elevations. Soft, faceted powder still prevails on polar aspects. Soft slabs in the upper 50cm can be found near ridge crests, but are more stubborn to move now. The Feb 10th surface hoar/suncrust is down 50-90cm and is much less reactive than a few days ago.
Avalanche Summary
Several loose, moist avalanches to size 3 were observed yesterday in the highway corridor, mainly off the steep south face of Tupper. These occurred during the heat of the late morning sun, which should provide incentive to get going early and use the solid overnight freeze as a safety buffer.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.
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.