Avalanche Forecast

Archived

Dec 9th, 2025–Dec 10th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Powell River, Spearhead, Tantalus.

A warm storm with mixed precipitation is approaching.

Avalanche hazard is expected to increase throughout the day Wednesday.

Avoid avalanche terrain during periods of heavy snowfall.

Confidence

Moderate

Avalanche Summary

A very natural large avalanche (size 2,5 or 3) occurred near Overseer Mountain this weekend from a leeward alpine slope, prone to loading with southerly winds.

Several explosive and human-triggered avalanches were reported in the Whistler/Blackcomb area over the last few days. These storm slabs ranged from size 1 to 2.5, with some stepping down to deeper buried layers like the Mid-November crust up to 1 m deep.

Snowpack Summary

15 to 25 cm of new snow can be found above 1800 m, which was redistributed by southerly winds in alpine and upper treeline terrain. This new snow will add to previous storm slabs that have formed over the last few days, which currently overlie older layers such as surface hoar, facets, and crusts.

A new breakable, melt-freeze crust is found at the surface at mid-elevation. The mid-November hard crust currently sits 60 to 120 cm deep with facets above and below. Some recent storm slabs have stepped down to this layer.

The snowpack height rapidly diminishes below 1100 m.

Weather Summary

Tuesday Night
Cloudy. Snow starting early evening. 50 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1500 m.

Wednesday
Cloudy. 30 to 50 mm of precipitation as snow or rain at treeline. 50 km/h southwest ridgetop wind. Treeline temperature 0°C. Freezing level rising to 1800 m.

Thursday
Mostly cloudy. 40 km/h northwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1500 m.

Friday
Cloudy. 5 to 10 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -4 °C. Freezing level 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid areas with overhead hazard.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Loose avalanches may start small, but they can grow and push you into dangerous terrain.
Stick to simple terrain or small features with limited consequence.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.