Avalanche Forecast

Archived

Mar 30th, 2025–Mar 31st, 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 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

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

Deeper weak layers are still a concern in the snowpack. Travelling on low angle slopes with minimal exposure to overhead hazard is still advised. Natural avalanche activity has tapered, but human triggering remains likely at upper elevations.

Confidence

High

Avalanche Summary

Small loose dry avalanches were observed in steep Alpine terrain on Sunday, particularly on solar aspects. Further evidence was observed of the earlier natural slab avalanche cycle up to size 4. Slopes that have not yet avalanched should be treated with extreme caution.

Snowpack Summary

Moist surface snow on solar aspects to ridgetop, and all aspects below 2200m on Sunday, coupled with cold overnight temps, means that we can expect a surface crust on Monday morning of varying thicknesses. Only sheltered north aspects will avoid this condition. At treeline an average of 30cm of recent storm snow overlies the Mar 28 crust. This crust is 10cm thick at valley bottom, and 5cm thick at treeline, which easily carries the weight of a skier. 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 to likely in these areas. Forecasters continue to have low confidence in the snowpack due to an exceptionally weak base with dense slabs over top.

Weather Summary

Temps will drop to around -12C Sunday night, and should provide a good freeze. Monday will be mostly cloudy with light southerly winds. A daytime high of -1C is expected at treeline elevations. No precipitation is expected. freezing levels are expected to climb to 2200m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Keep in mind that human triggering may persist as natural avalanches taper off.
Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.
Avoid shallow snowpack areas, rocky outcrops, and steep terrain where triggering is most likely.

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.