Avalanche Forecast
Regions: Coquihalla, Manning, Skagit.
Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Confidence
Moderate
Avalanche Summary
On Tuesday, a size 3.5 persistent slab avalanche was observed on a north aspect in the alpine that likely failed last weekend. Several loose wet avalanches on sunny slopes were also observed in this MIN post.
Looking forward: New snow and wind in the alpine may have built isolated, but reactive wind slabs on leeward (north though east) facing slopes.
Reports have been very limited. Please consider sharing your observations to the MIN.
Snowpack Summary
Recent rain and warming have saturated the upper snowpack on all aspects and elevations, except high north-facing alpine slopes. A crust will likely form as temperatures cool, and a dusting of around 5 cm of new snow falls overtop the moist/wet surface snow. Below 1800 m, the snowpack has shrunk considerably. A weak layer of facets and surface hoar from February is now 90 to 150 cm deep, and a layer of facets and surface hoar from late January is buried 110 to 190 cm. Below this, the snowpack is generally well-settled and strong.
Weather Summary
Thursday Night
Cloudy with 2 to 5 cm of snow above 1500 m, potential rain below. 15 to 25 km/h south ridgetop winds. Treeline temperature -2 °C. Freezing level 1800m, dropping to 1500 m.
Friday
Partly cloudy, with up to 2 cm of snow, potential rain below. 15 to 30 km/h south ridgetop winds. Treeline temperature 0 °C. Freezing level rising to 1700 m.
Saturday
Cloudy with 1 to 5 cm of snow above 1300 m, potential rain below. 25 km/h southwest ridgetop winds. Treeline temperature +2 °C. Freezing level rising to 1600 m.
Sunday
Sunny. 15 to 25 km/h southeast ridgetop winds. Treeline temperature +3 °C. Freezing level rising to 2100 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid freshly wind-loaded terrain features.
- Be alert to conditions that change with elevation, aspect, and exposure to wind.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and slopes above cliffs.
Avalanche Problems
Wind Slabs
Recent snow accompanied by south winds have built potentially reactive wind slabs on lee slopes at treeline and above.
Wet loose avalanches may be possible where precipitation falls as rain at lower elevations.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
A weak layer from January consisting of a melt-freeze crust with facets is buried 90 to 150 cm. This layer is most concerning in the south and east parts of the region in shallower snowpack areas.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3.5