Avalanche Forecast
Regions: Brandywine, Homathko, Sea To Sky, Spearhead.
Very dangerous avalanche conditions exist. Manage the uncertainty around buried weak layers by sticking to low-angle non avalanche terrain and avoiding overhead hazard.
Confidence
Moderate
Avalanche Summary
Thursdays was very active for avalanche observations and occurrences. Many persistence slab avalanche where triggered during explosive work and where large (size 3) . These avalanches had crowns greater than 100 cm in depth and 100 to 200 meters wide. A few avalanche where remote triggered by skiers.
On Wednesday 2 notable large (size 2) one a skier and one that was remotely triggered avalanches where reported in the whistler region.
Snowpack Summary
Storm snow amounts are forecast around 40 cm and overlie a variety of surfaces including surface hoar. Expect strong south winds to strip snow from ridgelines and exposed features and deposit new snow into deep pockets in lee aspect terrain.
Under the new snow an estimated 120-160 cm of progressively resistant or 'right side up' snow is continuing to settle above the problematic crust/facet/surface hoar layer beneath it. This layer continues to show sensitivity to human triggers, and is most concerning at treeline elevations where weak grains like facets and surface hoar are more easily preserved.
Weather Summary
Friday night
Cloudy increasing snowfall bringing 20-40 cm of new snow, 50-90 km/h southwest alpine wind. Treeline temperature -2 °C with freezing level rising to 1200 m.
Saturday
Cloudy with snowfall bringing 15-25 cm of new snow, continuing overnight. 60-80 km/h southwest alpine wind. Treeline temperature around -2 °C with freezing level rising to 1200 m.
Sunday
Cloudy with continuing heavy snowfall bringing 10-20 cm of new snow and 2-day totals to 50-80 cm. 20-40 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1200 m.
Monday
Cloudy with snowfall bringing 5-10 cm of new snow. 40-60 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Travel in alpine terrain is not recommended.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Avoid traveling in runout zones. Avalanches have the potential to run to the valley floor.
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
Avalanche Problems
Persistent Slabs
Buried weak layers are most concerning at treeline elevations. Small avalanches may step down to this layer resulting in very large destructive avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3
Storm Slabs
A new storm slab will bury the persistence slab and add additional load. There is potential for this storm slab to step down to the persistent slab depths.
Strong southwest winds will transport new snow onto lee aspect terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1.5 - 3