Avalanche Forecast

Archived

Feb 24th, 2025–Feb 25th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

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.

Regions

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

Avalanche conditions remain dangerous.

Stick to low angle, conservative terrain without overhead hazard.

Confidence

Moderate

Avalanche Summary

On Sunday widespread avalanche activity was observed, naturally (including solar induced) and human triggered to size 2.5. Avalanches were observed within the storm snow and on both buried persistent weak layers. Remotely triggered avalanches were also reported on these persistent layers, on north and east facing slopes at treeline.

We expect natural activity to taper off, but human triggering will remain likely.

Snowpack Summary

Storm totals reach 40 to 70 cm. Moderate to strong southwest winds have likely redistributed this snow into deeper and more reactive deposits at treeline and above. Below 1500 m precipitation mostly fell as rain.

This storm snow sits over surface hoar or thin crust from mid-February. Another weak layer of faceted snow /surface hoar/and a crust from late January is buried 60 to 100 cm deep. Both of these weak layers are expected to be more reactive from the heavy snowfall and warm temperatures. The remainder of the snowpack is generally well-settled.

Weather Summary

Monday Night

Cloudy with 10 to 15 cm of snowfall expected for most areas. 20 to 30 km/h south ridgetop wind. Freezing level drops to 1000 m.

Tuesday

Cloudy with another 10 to 15 cm of snow possible over the day. Heaviest amounts expected for Kootenay Pass. 30 km/h south ridgetop wind. Treeline temperature -4 °C. Freezing level rising to 1500 m.

Wednesday

A mix of sun and cloud. 20 to 30 km/h southwest ridgetop winds. Treeline temperature -3 °C. Freezing level rising to 1700 m.

Thursday

A mix of sun and cloud. 40 to 50 km/h southwest ridgetop winds. Treeline temperature -2 °C. Freezing level rising to 1800 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.

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.