Watch for the development of shallow storm slabs and fast moving loose dry avalanches as storm totals stack up Thursday. A natural cycle may be underway by Thursday night as the storm snow overwhelms the widespread buried surface hoar.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
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, 1 to 5 cm of snow possible.THURSDAY: Overcast, freezing level near valley bottom, light south wind at most elevations with strong west/southwest wind at ridgetop, 5 to 15 cm of snow possible during the day, 10 to 30 cm possible Thursday night.FRIDAY: Overcast, freezing level at valley bottom, light southwest wind at most elevations with strong southwest wind at ridgetop, 10 to 15 cm of snow.SATURDAY: Broken cloud cover, freezing level at valley bottom, moderate to strong southwest wind, 1 to 5 cm of snow possible.
Avalanche Summary
On Tuesday reported avalanche activity was limited to a size 2 cornice failure above a southeast facing slope at 2500 m. No new avalanche activity reported on Monday. On Sunday cornice failures to size 1.5 were observed on north through east facing terrain around 2000 m. Small natural wind slab avalanches to size 1 were reported on east and northeast facing terrain between 2000 and 2300 m.On Saturday a skier triggered a small persistent slab avalanche on an east facing feature at 2000 m, failing on the mid-January surface hoar.
Snowpack Summary
Saturday delivered warmth and wind to the region, followed by 10 to 15 cm of new snow and a very strong wind event on Sunday. This
MIN report provides a good description along with some photos that encompass conditions Sunday. The weekend weather left a crust on steep south facing aspects and redistributed quite a bit of snow into potentially deep wind slabs in lee features at and above treeline. These wind slabs have grown old and tired, and are probably only susceptible to triggering in extreme terrain. 15 to 45 cm of snow continues 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 1500 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.
ghelgeson,
Avalanche Canada
