Avalanche Forecast

Archived

Apr 26th, 2023–Apr 29th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Below Threshold.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Regions

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

We are entering the first massive warm up of the season. Freezing levels are to continually rise to 3000m by Friday and even higher throughout the weekend. Use extreme caution if considering heading in to avalanche terrain, A large avalanche cycle is expected throughout this warming and will likely run to the end of avalanche runouts. Avalanche canada will be issuing an SPAW (Special Public Avalanche Warning) On Thursday. Check out avalanche canada for updates.

Confidence

Moderate

Avalanche Summary

No new avalanches observed today.

With the incoming warm temps and rapidly rising freezing levels, An avalanche cycle is expected to happen when the freezing levels rise to well over 3000m and the snowpack does not recover overnight from cold temps. These have the potential to reach the end of the run out zones and be very destructive. The deep persistent slab problem will most likely wake up through this warming event.

Snowpack Summary

The snowpack is finally starting to adjust to the warm temps and the transition to a spring snowpack is starting. Surface snow conditions are frozen in the morning and becoming moist by noon. 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.

Weather Summary

Thursday will be a mix of sun and cloud and day time highs around zero. This is the first day of a constant warming over the next 5 days. where freezing levels are expected to rise over 3000m (Mountain top) by Friday. Winds will be light overall.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Keep in mind that wet avalanches can be destructive due to their high density.
If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.

Problems

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.