Avalanche Forecast

Archived

Feb 26th, 2025–Feb 27th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, 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.

Problems

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.

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.