Avalanche Forecast

Archived

Dec 23rd, 2025–Dec 24th, 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 unlikely, human triggered possible.

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.

Regions

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

Over 100 cm of new snow has fallen this week, and it needs time to settle and bond.

Stormy conditions on Wednesday will continue to build slabs that could be surprisingly deep and reactive.

Confidence

Moderate

Uncertainty is due to difficult to forecast freezing levels.

Avalanche Summary

On Sunday, a snow cat in the Whistler area triggered a size 2 persistent slab on a northwest aspect in the alpine.

On Monday, skiers in the Whistler area triggered size 1 storm slabs in lee terrain features in alpine and treeline terrain. Observations were limited by stormy conditions.

Looking forward to Wednesday, fresh, reactive storm slabs are expected to build with snowfall, wind, and warming.

Snowpack Summary

Up to 20 cm of new snow by end of day Wednesday overlies over 100 cm of settled storm snow from the past week. Strong southerly winds have left a variety of surfaces - wind slabs and loaded pockets in lee features, scoured rock in open terrain, and storm slabs and softer snow in sheltered areas.

This week's storm snow buries a melt-freeze crust that exists at 2200 m and below. The depth of this crust is highly variable due to extensive recent wind transport.

A crust with facets, formed in mid-November, is buried an estimated 80 to 150 cm deep. With limited observations, especially in the alpine (which did not have the same mid-pack crust development), we're not ready to rule out this layer of concern quite yet.

Weather Summary

Tuesday Night
Partly cloudy. 1 cm of snow. 10 km/h southeast ridgetop wind. Treeline temperature -5 °C.

Wednesday
Cloudy. 15 to 20 cm of snow. 20 to 50 km/h southeast ridgetop wind. Treeline temperature -4 °C.

Thursday
Mix of sun and clouds. 1 cm of snow. 15 km/h southeast ridgetop wind. Treeline temperature -4 °C.

Friday
Mostly cloudy. 1 to 4 cm of snow. 10 km/h southwest ridgetop wind. Treeline temperature -7 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

It's a good day to make conservative terrain choices.
Don't let the desire for deep powder pull you into high consequence terrain.
Be especially cautious as you transition into wind-affected terrain.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

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.

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.