Avalanche Forecast
Regions: Coquihalla, Harrison-Fraser, Manning, Skagit.
Avoid avalanche terrain
Natural avalanche activity is expected with heavy snowfall and strong winds.
Confidence
Moderate
Avalanche Summary
No recent avalanches have been reported.
Widespread natural avalanche activity is expected to begin on Sunday as snow and wind develop sensitive slabs.
Snowpack Summary
By Sunday evening, up to 60 cm of new snow is expected, falling over a variety of surfaces. Most concerning is the large surface hoar found in sheltered terrain, and a crust on south-facing slopes and all aspects below treeline. In exposed terrain at high elevations, new snows fall on old wind-affected snow.
A widespread crust is now buried 65-100 cm below the surface with weak, faceted snow immediately above it. Surface hoar was previously found above the crust in some parts of the region. Operators in the Hope area observed several whumpfs on this layer on shaded treeline slopes Thursday. Uncertainty exists over whether this layer will become active with the heavy load of new snow.
Weather Summary
Saturday Night
Cloudy with up to 20 cm of snow expected. 40-50 km/h southwest winds expected. Freezing levels remain around 1300 m.
Sunday
Cloudy heavy snowfall continuing, 20-40 cm of snow expected - heaviest in the southwest. 60 - 80 km/h southwest winds increasing over the day. Treeline temperature -3 °C with freezing levels around 1300 m.
Monday
Up to 20 cm of snowfall is possible overnight, again favoring the southwest. Snow tapers off on Monday morning with light flurries likely over the day.
Mostly cloudy with possible sunny breaks in the afternoon. Southwest winds ease, 30-40 km/h. Treeline temperature -5 °C with freezing level falling to 300 m.
Tuesday
A mix of sun and cloud with no snowfall expected. 30-40 km/h southwest winds. Freezing levels at valley bottom, treeline temperatures of -8 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
Avalanche Problems
Storm Slabs
Storm slabs will build over the day as new snow accumulates over large surface hoar or a crust. Deeper deposits are expected in north and east facing terrain around ridgelines.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Persistent Slabs
A problematic combination of weak faceted snow and/or surface hoar over a crust remains a concern in isolated treeline terrain.
Aspects: North, North East, East, North West.
Elevations: Treeline.
Likelihood: Possible
Expected Size: 1 - 2.5