Avalanche Forecast

Archived

Feb 24th, 2025–Feb 25th, 2025

Alpine

Natural avalanches possible, human triggered probable.

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

South Coast Inland, Birkenhead, Duffey, South Chilcotin, Stein, Taseko.

Our persistent weak layer is getting more sensitive.

Dangerous avalanche conditions exist and several evidences are observed.

Adopt a conservative mindset when in avalanche terrain.

Confidence

High

Avalanche Summary

A large-scale natural avalanche cycle (size 3) was observed after Sunday's storm from steep northerly slopes at treeline and above. Several skiers-remote persistent slabs were also reported on the persistent layers down 40 to 50 cm deep in the snowpack in the region. See this MIN near Rohr Summit. There are reports of wind contributing to slab development over this layer.

Snowpack Summary

10 to 20 cm of new snow accumulated overnight Sunday, bringing the total of storm snow to 50 to 60 cm and overlying various problematic surfaces formed during recent cold, dry conditions. These include weak surface hoar or faceted grains in sheltered, shaded terrain, and sun crusts on sun-affected slopes. This layer was responsible for numerous remote triggered observed Sunday and Monday in the region.

A layer of hard crust buried in late January, currently sitting beneath weak facets and less widespread surface hoar is now 40 to 80 cm deep. Some recent avalanches have failed on it. It's particularly active closer to Whistler.

The snowpack below is strong.

Weather Summary

Monday Night

Cloudy with 5 to 10 cm of new snow. 30 to 50 km/h south ridgetop wind. Treeline temperature stable around -4°C. Freezing level around 1400 m.

Tuesday

Mostly cloudy with isolated flurries. 15 to 25 km/h southwest ridgetop wind. Treeline temperature stable around 0°C. Freezing level reaching 1700 m.

Wednesday

Partly cloudy. 20 to 30 km/h south ridgetop wind. Treeline temperature stable around +2°C. Freezing level reaching 2200 m.

Thursday

Cloudy with up to 5 cm of new snow. 40 to 60 km/h southwest ridgetop wind. Treeline temperature +2°C. Freezing level lowering to 1800 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
Be aware of the potential for large avalanches due to buried weak layers.
Avoid thin areas like rocky outcrops where you're most likely to trigger avalanches on deep weak layers.

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.