Avalanche Forecast

Archived

Apr 21st, 2023–Apr 22nd, 2023

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

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

Decent skiing continues to be found on polar aspects where the sun hasn't touch it. Continue to start early and finish early as good spring habits.

Confidence

Moderate

Avalanche Summary

No field teams today.

No avalanches reported.

Snowpack Summary

15-20 cm of recent snow overlies a variety of surfaces such as wind slabs and melt/freeze crusts. Sheltered areas and polar aspects will provide the best skiing with little wind effect. Be aware of sluffing on solar aspects if the sun comes out. Forecasters continue to track persistent weaknesses down anywhere from 40 to 100cm on polar aspects. These weaknesses are highly variable in nature and travelers should take the time to dig down and evaluate the snowpack frequently. Also, the lingering deep persistent slab problem is still alive and well.

If the sun comes out stability will deteriorate quickly so pay attention to the incoming radiation on aspects you are travelling on or under. Early starts and finishes are a great way to deal with some of these issues.

Weather Summary

Continued cloudy conditions with trace amounts of snow in the forecast for the weekend.

Winds are lighter, 20km out of the SW swapping to west on Saturday.

Day time highs of -4 and freezing levels around 2100m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.