Avalanche Forecast
Regions: Coquihalla, Harrison-Fraser, Manning, Skagit.
Monitor new snow depths and reactivity as the storm gets started. Wind loaded features and places large surface hoar is being buried will likely be the first to reveal instability.
Confidence
Moderate
Avalanche Summary
No new avalanches have been reported in the region in quite some time. The situation should begin to shift on Saturday as up to 15 cm of new snow and elevated southwest winds invade. Small new wind slabs will be the initial concern on Saturday. By Sunday we should see touchy storm slabs forming over an array of problematic surfaces.
Snowpack Summary
Up to about 15 cm of new snow should accumulate in the region through Saturday. It will add to a skiff of windblown snow that recently began to bury a variety of surfaces including large surface hoar in sheltered terrain, a crust on south aspects and on all aspects below treeline, and old wind-affected surfaces in exposed terrain.
A widespread crust exists 25-40 cm below the surface with up to 5 cm of weak, faceted snow immediately above it. Surface hoar was previously found above the crust in some parts of the region. Old, likely stubborn wind slabs formed over this problematic layering are a lingering concern. Operators in the Hope area observed several whumpfs on this layer on shaded treeline aspects Thursday.
Weather Summary
Friday night
Becoming cloudy then flurries bringing around 5 cm of new snow or just over. 40 to 50 km/h southwest alpine wind, increasing. Freezing level falling to 1100 m.
Saturday
Cloudy with continuing flurries bringing 5-10 cm of new snow. 40-50 km/h southwest alpine wind. Treeline temperature -3 C with freezing level to 1300 m.
Sunday
Cloudy with moderate to heavy snowfall bringing 20-30 cm of new snow, including overnight amounts. 60 - 80 km/h southwest alpine winds, increasing. Treeline temperature -3 °C with freezing level to 1300 m.
Monday
Cloudy with diminishing flurries bringing 15-25 cm of new snow, including overnight amounts. 20 - 30 km/h west or southwest alpine winds, easing. Treeline temperature -5 with freezing level falling to 600 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Wind slabs are most reactive during their formation.
- Carefully evaluate steep lines for wind slabs.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Avalanche Problems
Wind Slabs
New wind slabs should begin to form across the region as new snow and wind arrive. This problem will increase over the day.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5
Persistent Slabs
A problematic combination of weak faceted snow and/or surface hoar over the early February crust remains a concern in isolated treeline terrain.
Aspects: North, North East, East, North West.
Elevations: Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2