Avalanche Forecast

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Friday

Thursday kicks off a multi-day snow event that should provide a nice re-set for the region. This is a dynamic period as northwest flow scoops up incoming weather systems off the east-pacific and directs them over the province. Take these snow totals with a grain of salt, amounts are changing quite drastically from one model run to the next. WEDNESDAY NIGHT: Freezing level near valley bottom, light variable wind at most elevations with strong northwest wind at ridgetop, trace of snow possible.THURSDAY: Overcast, freezing level near valley bottom, light southwest wind at most elevations with strong west wind at ridgetop, 1 to 5 cm of snow possible during the day, 5 to 15 cm possible Thursday night.FRIDAY: Overcast, freezing level near valley bottom, light southwest wind at most elevations with strong southwest wind at ridgetop, 10 to 20 cm of snow.SATURDAY: Broken cloud cover, freezing level near valley bottom, light to moderate southwest wind, trace of snow possible.

On Tuesday we received two reports of small wind slabs that were intentionally triggered by skiers on steep east and northeast facing slopes in the alpine. There was also a report of a size 2 cornice failure above a southeast facing slope. In the neighboring Glacier National Park region a size 3 avalanche was skier triggered on a steep southeast facing slope in the alpine. More details and photos here.For the most part, avalanche activity really slowed down Monday. That being said, a size 2 natural wind slab was reported from a NE facing feature at 2600 m. A small (size 1) avalanche was reported from a steep northeast facing slope below treeline at 1300 m, which failed on the surface hoar. Activity on this interface has decreased in the last 72 hours, but this MIN post and this one do a great job of illustrating the nature of this problem which is most prevalent between 1200 and 1800 m. This MIN is a bit older, but it also offers a great visual of this mid and low elevation problem. This interface will likely wake up as storm snow begins to stack up over the weekend.

The current snow surface is a mix of sastrugi, stubborn old wind slabs, facets, crust and surface hoar. Last saturday delivered warmth and strong to extreme wind out of the west, south, southwest and northwest. This left a crust up to 3 cm thick on steep south and some west facing aspects and redistributed quite a bit of snow into wind slabs in lee features at and above treeline. These wind slabs have grown old and tired and are probably only suspect in extreme terrain. The warmth also allowed 25 to 60 cm of snow to continue to consolidate above the mid-January persistent weak layer (PWL). This PWL is made up of large surface hoar that is most prevalent at and below treeline, with enhanced reactivity noted between 1400 and 1800 m. On steep solar aspects this interface presents as a crust, there may be locations where the surface hoar actually sits on the crust.The middle and lower portions of the snowpack are generally well-settled and strong.