Conservative route selection is advised. Watch for signs of slab formation especially in wind exposed terrain.
Weather Forecast
Mainly cloudy with isolated flurries. Alpine temperature of -11C and ridge top west winds in the 15-25km/h. The trend is toward clearing and cooling temperatures as high pressure moves in to start 2017.
Snowpack Summary
50cm of storm snow in 2 days, mod S winds at ridgetop should be building reactive wind slab in the alpine along with storm slab formation at all 3 elevation levels. Several weak layers were observed yesterday as the storm snow settles into a slab. Dec 18th facet/surface hoar layer should not be discounted and may wake with this extra load.
Avalanche Summary
Earlier in the week we had skiers report sensitive wind slab on SW aspect at 2100m on McGill. Now we have 50cm more snow load. Avalanche control east of the pass this morning is producing slides in the size 3 range.
Confidence
Due to the number of field observations
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.
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.