Avalanche Forecast
Regions: Brandywine, Garibaldi, Homathko, Sea To Sky, Spearhead, Tantalus.
Reactive storm slabs are likely at upper elevations. Stick with a conservative trip plan and watch for signs of instability.
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Confidence
Moderate
Avalanche Summary
On Wednesday, numerous human-triggered and explosieve-triggered storm slab avalanches were reported up to size 1.5 at treeline and below. Alpine observations were very limited due to the stormy conditions and poor visibility, but we suspect natural avalanches occurred.
Reactive storm slabs are likely on Friday, especially at upper elevations (northerly slopes) that see more wind loaded snow. Natural avalanche activity can spike on solar slopes when the sun is out.
Snowpack Summary
Another 30 cm blanketed the region by Thursday morning. Up to 120 cm of storm snow sits above a crust on all aspects except high north-facing slopes, where it sits on faceted snow that formed in early March. Strong southwest winds have redistributed storm snow into toucy slabs on leeward slopes at the ridgeline. Below treeline the storm snow is settling out rapidly.
A layer of facets and surface hoar from mid February can be found down 100 to 140 cm.
Another layer of facets and surface hoar from late January can be found down 140 to 200 cm.
Weather Summary
Thursday Night
Cloudy with some clear periods and flurries up to 5 cm. 15 to 20 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.
Friday
Cloudy with some sunny periods and isolated flurries. 10 to 20 km/h southeast ridgetop wind. Treeline temperature -4 °C. Freezing level 1100 m.
Saturday
Cloudy with 5 to 10 cm of snow. 25 to 40 km/h south ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.
Sunday
Cloudy with snow 5 to 10 cm. 15 to 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1300 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid lee and cross-loaded slopes at alpine and treeline elevations.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Even brief periods of direct sun could produce natural avalanches.
- Storm slabs in motion may step down to deeply buried weak layers and result in very large avalanches.
Avalanche Problems
Storm Slabs
Storm slabs continue to be reactive to human triggering. Stick to simple terrain. Back off if you encounter signs of instability like warming from the sun, whumpfing, shooting cracks or recent avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Weak layers remain a concern in high, north-facing terrain where snowpack depth is variable. These layers are still adjusting to the new snow load and have recently been reactive.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 2 - 3