The SOUTH end of the region has significantly more new snow and will take more time to stabilize. Be aware that the sun's rays can have a de-stabilizing effect on the new snow. Be cautious if the sun burns off the high clouds.
Weather Forecast
Friday: Expect mostly sunny skies, with a chance of high, thin cloud. Winds should be light from the north and alpine temperatures should reach -4.Saturday & Sunday: Expect the ridge to settle in. Sunny skies, light northerly winds and alpine temperatures reaching -1 each afternoon.
Avalanche Summary
We have reports of natural, explosive and rider triggered windslabs up to size 2.5 failing on northwest through east facing terrain. These are failing predominantly at treeline and in the alpine. Remote and accidental triggering have been observed. The south end of the region has seen the larger releases with wider propagation; at times linking terrain around ridge features. These areas have also seen storm slab events on open, convex features below treeline.
Snowpack Summary
A final pulse of new snow has fallen bringing storm totals to between 30cm (north end of the region) and 90cm (south end of the region). Consistent southerly winds during the storm period has built windslabs in lee terrain. Warm temperatures have consolidated storm slabs on open convex features where the new snow is deepest. Newly buried surfaces include old windslabs, temperature and sun crusts. The new snow is bonding reasonably well at this interface in most locations with the highest concern being the bond to crusts on south and west facing terrain. The January 23rd interface (crusts, facets and surface hoar crystals) lingers in isolated locations. This layer seems to be rounding and bonding under current conditions, but we have reports of a recent size 2.0 releasing on this layer at the north end of the region. The mid pack is generally well settled with the average snowpack depth at treeline around 180 cm.
Problems
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.