Avalanche Forecast

Fair - Freezing levels are uncertain

A strong, stable northwesterly flow will prevail over the province while a strong upper ridge remains offshore. The ridge should weaken somewhat on Tuesday but will still protect the province from Pacific systems.Monday: Mainly dry conditions, freezing level at valley bottom with a chance of a temperature inversion bringing warmer temperatures to upper elevations.  Temperatures approaching 0 degrees or slightly warmer between 2000 and 2800m. Winds Moderate to strong from the west and northwest.Tuesday: Mainly cloudy, no precipitation, alpine temperatures -8, light west winds.Wednesday: A Pacific frontal system starts to affect the interior regions. Cloudy with light snowfall, moderate to strong west winds. Freezing level in the valley bottom.

Recent reports continue to indicate avalanche activity from Thursday and Friday's avalanche cycle as the snowpack adjusted to the new load. Avalanches were running naturally to size 3.5 with many reports of runouts filled with debris. Skiers triggered avalanches both intentionally and accidently to size 2. While the large avalanches likely dug into deeply buried weak layers, it appears as though much of the activity was limited to the storm snow or the mid December surface hoar. 

Thursdays storm delivered 20 - 50 cm of new snow bringing the average regional depth to 160 - 240cm.This new snow lies on top of old wind slabs, a thin melt freeze crust below 2100m and numerous weak layers. Down 40 -100cm is the mid December layer comprised of surface hoar, stellars and/or a crust. Around 70 -140cm down is the early December surface hoar, faceted snow and/or crust.There are two deeper layers of note. The late-November persistent weak layer consists of a sun crust on steep south facing slopes and surface hoar in sheltered areas and is now buried 90-160cm below the surface. The October deep persistent weak layer consists of a layer of facets sitting on a crust at the base of the snowpack. This layer is predominantly found on northerly aspects at treeline and in the alpine. The depth of both these layers makes directly triggering an avalanche on them unlikely (maybe a heavy load on a thin spot in steep terrain). Their presence could, however, increase the size of a potential avalanche through step-down.