Avalanche Forecast
Regions: Brandywine, Garibaldi, Homathko, Sea To Sky, Spearhead, Tantalus.
The sensitive persistent weak layer remains our main concern at treeline and above.
Rider-triggered avalanches are likely, and avalanches can be destructive.
Confidence
Moderate
Avalanche Summary
In Whistler, explosive controls triggered a large persistent slab (size 2.5) on north alpine slopes. The suspected layer is the late-Jan/early Feb persistent layers. Few natural slabs (size 2.5) were also observed Tuesday on north alpine slopes with large crowns, potentially on the same weak layer.
Evidence of natural avalanches from the past weekend's storm is still visible throughout the region. One impressively large was reported on the MIN near Russet Lake.
Snowpack Summary
The region received 60 to 80 cm since the last storm but settled quickly on Wednesday. A thin sun crust is visible up to 2000 m on southerly slopes, while extensive strong southerly winds have redistributed recent snow and scoured exposed areas at treeline and alpine.
The storm snow covers weak surfaces, including faceted snow, or surface hoar in sheltered terrain.
A weak layer, buried at the end of January, is now 80 to 120 cm deep in the snowpack. This may present as a crust on sunny slopes, sugary facets in most places, and surface hoar in sheltered spots. Natural avalanches and human triggering have been reported on this concerning weak layer since Sunday.
Weather Summary
Wednesday Night
Mostly clear. 50 to 60 km/h south ridgetop wind. Treeline temperature stable around +0°C. Freezing level around 1800 m.
Thursday
Cloudy with 5 to 10 cm of new snow. 40 to 60 km/h southwesterly ridgetop wind. Treeline temperature +2°C. Freezing level reaching 2200 m.
Friday
Partly cloudy. 20 to 30 km/h south ridgetop wind. Treeline temperature +2°C. Freezing level reaching 2200 m.
Saturday
Partly cloudy. 30 to 50 km/h southeast ridgetop wind. Treeline temperature +2°C. Freezing level reaching 2200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
Avalanche Problems
Wind Slabs
Reactive wind slabs will be sensitive to rider triggers in lee terrain near ridge tops and on cross-loaded features. At higher elevations, these slabs have the potential to step down to deeper layers and produce large avalanches.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Persistent weak layers have become active with increased load and warm temperatures. A small wind slab may also step down to produce larger avalanches. Avoid shallow areas where triggering slabs are more likely.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 3