Winter conditions persists in the alpine with 10cm of new snow. Several crusts are buried in the upper snowpack and may be triggered by recently formed reactive wind slabs. Expect variable (challenging) ski conditions below treeline.
Weather Forecast
A mix of sun and cloud accompanied by isolated convective flurries. Ridge winds will be west 25km/h gusting to 50km/h. Freezing levels stay below1400m, but the afternoon sun can have a profound effect on steep solar aspects at all elevations. Temperatures climb higher on Sunday moving us towards spring conditions with warm days and cool nights.
Snowpack Summary
10cm of new snow at treeline. Settling storm snow in the top 60cm overlies a series of crusts on most aspects up to 1900m. Strong to extreme winds in the high alpine have formed wind slabs on lee features. Cold, dry snow can be found on northerly slopes while solar aspects rapidly become moist with sunshine. Huge cornices line the upper ridges.
Avalanche Summary
Several large natural avalanches were observed in the highway corridor yesterday in the size 2.0-2.5 range. Two size 3.0-3.5 avalanches were observed on the north face of Mt MacDonald including a deep slab release that cleared trees and ran to the end of the run out zone.
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.