Avalanche Forecast

Archived

Mar 14th, 2025–Mar 15th, 2025

Alpine

Natural avalanches possible, human triggered probable.

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, Ymir, Crawford, Moyie, Kokanee, Retallack, Valhalla, Whatshan.

Choose gentle, low consequence lines and avoid overhead hazard.

Check out the forecaster blog for a detailed conditions update.

Confidence

Moderate

Avalanche Summary

Thurs: A widespread region-wide avalanche cycle of natural and human-triggered avalanches occurred, with slabs up to size 3 (very large). The majority occurred on north and east facing slopes

Tues/Wed: Several size 1-1.5 natural and skier-triggered storm and wind slab avalanches occurred.

Looking forward: Storm slabs are expected to remain reactive and may step down to deeper persitstent weak layers.

Snowpack Summary

20 to 40 cm of new snow fell in the last storm creating widespread and reactive storm slabs. Up to 10 cm of additional snow may fall on Saturday. Lower elevations and sun-affected slopes may have moist or crusty surface snow.

There is potential for the new snow to overload persistent weak layers in the upper to mid snowpack, causing storm slabs to step down to deeper layers. These include:

Facets/surface hoar/crust from early March buried 25-50 cm.
Facets/surface hoar/crust from mid-February buried 40-90 cm
Facets/surface hoar/crust from late January buried 80-120 cm.

The rest of the snowpack is well settled with no other layers of concern.

Weather Summary

Friday Night

Partly cloudy with up to 2 cm of snow. 15 to 25 km/h southwest ridgetop wind. Treeline temperature -8 °C.

Saturday

Cloudy with 3 to 10 cm of snow. 20 to 40 km/h south ridgetop wind. Treeline temperature -5 °C.

Sunday

Cloudy with 2 to 10 cm of snow. 20 to 30 km/h south ridgetop wind. Treeline temperature -4 °C.

Monday

Partly cloudy with 0 to 5 cm of snow. 15 to 30 km/h west ridgetop wind. Treeline temperature -5 °C.

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.
Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
Be aware of the potential for human triggerable storm slabs at lower elevations, even on small features.
Be especially cautious as you transition into wind-affected terrain.

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.