Avalanche Forecast

Archived

Feb 15th, 2025–Feb 16th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, Ymir, Crawford, Moyie.

Fresh wind slabs are forming on lee slopes and triggering persistent slabs remains possible.

Retreat to more conservative terrain if you experience signs of instability.

Confidence

Moderate

Avalanche Summary

On Friday a few naturally-triggered wind slabs were observed near Kootenay Pass from lee southerly slopes. A remotely-triggered slab was also observed there on a steep bank below treeline.

On Wednesday a rider remotely triggered a persistent slab avalanche (size 2) on an east-facing slope just above 2000 m. (See photo below)

Dry loose sluffing continues to be observed from steep terrain features.

Snowpack Summary

Exposed terrain in the alpine and treeline is variably wind-affected. Up to 10 cm of new snow is expected in some areas by the end of the day Sunday. This will add to a recent snowfall of around 5 cm, which is covering a layer of surface hoar in many areas, or a thin suncrust on steep south-facing slopes. Below that, 20 to 60 cm of faceted snow overlies a persistent weak layer from late January. This layer consists of a crust on sun-exposed slopes and surface hoar on all other aspects. Recent snowpack tests indicate that an overlying stiff and consolidated slab is generally required for it to be reactive. The remaining is generally well settled.

Weather Summary

Saturday Night

Cloudy with 2 to 5 cm of snow. 20 to 25 km/h south ridgetop wind. Treeline temperature -10 °C.

Sunday

Cloudy with 3 to 6 cm of snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -9 °C.

Monday

Cloudy with 0 to 3 cm of snow. 15 km/h variable ridgetop wind. Treeline temperature -8 °C.

Tuesday

Sunny. 10 to 25 km/h northwest ridgetop wind. Treeline temperature -7 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be careful as you transition into wind-affected terrain.
Approach steep and open slopes at and below treeline cautiously, as buried surface hoar may exist.
Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or 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.