Avalanche Forecast

Archived

Apr 3rd, 2025–Apr 6th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Early starts with early finishes are both good ideas as the sun has lots of punch these days. Friday will have clear skies and high freezing levels so we are expecting solar aspects to become sensitive to trigerring later in the day. Good skiing is still being found on north aspects.

Confidence

High

Avalanche Summary

Loose dry avalanches up to sz 1 in the recent snow from steep unskiable terrain.

Snowpack Summary

At treeline, an average of 30-40cm of recent snow overlies the Mar 28 crust which carries the weight of a skier. Take the time to monitor the presence of this crust; if it is not there, then there could be a higher likelihood of triggering the basal facets. The Jan 30th layer buried 60 to 100cm deep is still a concern. It could become active with intense heating (daytime temps and/or solar input), and it is also problematic on northern aspects at higher elevations and in shallow snowpack areas. Human triggering is possible as well in these areas.

Solar aspects are a mixture of crusts and more challenging skiing. AS these crusts break down during the day, expect stability to decrease and avalanches become more likely.

Weather Summary

Overnight lows forecast to drop to -15C overnight. No new snow forecast and winds are expected to be light out of the NW. Skies will be clear and the freezing will climb to 2100m so expect stability to deteriorate on solar aspects later in the day.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be alert to conditions that change with elevation and sun exposure.
Avoid shallow snowpack areas, rocky outcrops, and steep terrain where triggering is most likely.
Avoid exposure to overhead hazards when solar radiation is strong.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.