Avalanche Forecast

Archived

Mar 4th, 2025–Mar 5th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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

South Rockies, Akamina, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West.

***Updated 7:10***

Remain especially cautious on high northerly slopes & areas without a thick supportive crust under the new snow.

Confidence

Low

Avalanche Summary

Sun: Several small loose wet avalanches were ski cut and one size 2 natural avalanche occurred near Castle Mtn.

Fri /Sat: Naturally triggered size 2.5 persistent slabs occurred near Castle Mtn. They ran on the persistent weak layer, approximately 50 cm deep.

Looking forward: Fresh wind slabs may be reactive and have potential to step down to deeper layers on Wednesday.

Snowpack Summary

Up to 15 cm of new snow is expected to fall overnight and through Wednesday. Southwesterly winds may build fresh and reactive wind slabs on lee north and easterly slopes. The new snow will be falling on a widespread melt-freeze crust that exists everywhere but high north-facing slopes. The main feature of the region's overall shallow snowpack is a persistent weak layer of surface hoar or facets from late January now buried 40 to 60 cm deep (see photo below). This layer was active during the warm-up and remains a concern where a thick and supportive crust under the new snow hasn't stabilized the snowpack.

Weather Summary

Tuesday Night

Cloudy with 2 to 5 cm of snow. 25 km/h southwest ridgetop wind. Treeline temperature around -6 °C. Freezing level 1600 m, then falling to valley bottom.

Wednesday

Cloudy with 2 to 10 cm of snow. 10 to 25 km/h west ridgetop wind. Treeline temperature around -3 °C. Freezing level rising to 1600 m.

Thursday

Mostly sunny. 10 to 15 km/h northeast ridgetop wind. Treeline temperature around -1 °C. Freezing level rising to 1800 m.

Friday

Sunny. 20 km/h west ridgetop wind. Treeline temperature around 1 °C. Freezing level rising to 2000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Avoid freshly wind-loaded features, especially near ridge crests, rollovers, and in steep terrain.
Use ridges or ribs to avoid areas of wind-loaded snow.
Be mindful that deep instabilities are still present and have produced recent large avalanches.

Problems

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.

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.