Avalanche Forecast

Archived

Dec 23rd, 2025–Dec 24th, 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

East Purcell, St. Mary.

Keep an eye out for new wind loading.

New wind slabs are the primary concern on exposed features.

Sheltered terrain holds great riding conditions.

Confidence

Moderate

Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
The snowpack structure is generally well understood.

Avalanche Summary

Sluffing in steep terrain was observed on Monday, no slab avalanches have been observed in the region since Saturday. If you are travelling in the mountains, please submit any observations to the Mountain Information Network.

On Friday near Invermere, an explosive triggered a size 1.5 persistent slab on a north-facing treeline slope, failing on a crust 80–110 cm deep. Over the weekend several rider triggered wind slabs were reported up to size 1.5 on north facing slopes.

Snowpack Summary

Around 20 cm of new snow accompanied by southerly wind is expected by Wednesday afternoon. This falls over 40 to 80 cm of wind affected, settling snow that is generally bonding well to the mid December crust, which is present up to approximately 2100 m.

A thick mid-November crust is buried 70–110 cm deep in eastern terrain, and up to 180 cm in areas with a deeper snowpack. In most areas, faceted grains overlie the crust. Specific, sheltered terrain features have surface hoar present on or near the crust.

Depth hoar (large, weak crystals) are present at the base of the snowpack.

Weather Summary

Tuesday Night

Mostly cloudy with up to 5 cm of snow. 10 to 20 km/h south ridgetop wind. Treeline temperature -6 °C. Freezing level 900 m.

Wednesday

Mostly cloudy with 5 to 15 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -2 °C. Freezing level 1400 m.

Thursday

Mix of sun and clouds with 2 to 5 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1000 m.

Friday

Mostly cloudy with up to 15 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1000 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.
Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
Be mindful that deep instabilities are still present in the snowpack.

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.