Avalanche Forecast

A storm system impacts to the coast Wednesday night and Thursday before a warm ridge of high pressure establishes on Friday. 

Wednesday Night: Snowfall 20-30 cm, wind becoming moderate to strong SW, freezing levels 1200-1400 m. 

Thursday: Snowfall 15-30 cm, moderate to strong SW wind, freezing levels reaching around 1500 m.

Friday: Mainly sunny, light NW wind, freezing levels climbing to around 3000 m with an inversion. 

Saturday: Mainly sunny, light NW wind, freezing levels around 3200 m with an inversion. 

On Tuesday, explosives triggered three large cornices, none of which triggered slabs on the slopes below. Just north of the region on Tuesday, two human-triggered size 1-1.5 wind slabs were reported on NW-NE aspects at 1950 m. 

The new storm snow continues to bury a widespread melt-freeze crust below around 2100 m elevation. There have also been some observations of a new surface hoar layer but this does not appear to be widespread. At higher elevations, the new snow will bury wind affected surfaces and old wind slabs. The snow surface is reported to be moist or wet below around 1300 m elevation. 

The depth of the early December crust/facet layer is highly variable through the region but appears to be typically down 100-200 cm. Some operators are showing it as shallow as 60 cm and as deep as 3 m. The weak layer is most prominent between 1700 and 2100 m. With the recent cooler temperatures, the probability of triggering an avalanche on this layer has become low but it remains a concern for the period of major warming and sun forecast for the weekend. The most likely place to trigger it would be in thin, rocky snowpack areas where it is shallowest. 

• Storm slab size and sensitivity to triggering will likely increase through the day.
• Be alert to conditions that change with elevation and wind exposure.
• The more the snow feels like a slurpy, the more likely loose wet avalanches will become.