Confidence
Fair - Timing of incoming weather is uncertain on Saturday
Weather Forecast
Saturday: Moderate to heavy precipitation. Freezing level rising through the day to around 1300m. Strong to gale south-westerly winds at ridge top. Sunday: Light to moderate snow continues. Freezing level staying near 1200m. Strong westerly winds.Monday: A break from heavy snow, although light snow is possible, especially on western slopes. Freezing level falling back to valley floor.
Avalanche Summary
On Thursday, a skier remotely triggered a size 1.5 slab on a convex feature. It failed on facets beneath the storm snow. On Wednesday, three size 3.5 natural avalanches ran full path. A few other natural avalanches, up to size 2, were observed in steep lee (wind-loaded) terrain. Whumphing was observed below treeline.
Snowpack Summary
Up to 1m of snow has fallen since Monday. Strong winds have created hard slabs, soft slabs and fragile cornices. Snowpack tests give easy to moderate results on several layers in the upper snowpack. Key concerns as further snow builds this weekend include a weak facet layer that was created during the brutal cold snap in mid-January and a buried crust which is found below treeline.
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.