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Avalanche Forecast

Archived

May 7th, 2024–May 9th, 2024

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 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 a massive warm up.

Time to avoid all avalanche terrain and any exposure to avalanche run outs.

Scramblers be aware of what's overhead and stay out of gully's.

Confidence

High

Avalanche Summary

No new avalanche observations or reports the last few days. Forecasters have not been out on foot, but have driven the spray road. Wide spread wet activity is everywhere. This large warm up is a good opportunity for any slope that has not avalanched will likely wake up the deep persistent weak layers in the snowpack and be large destructive wet avalanche.

Snowpack Summary

With above freezing temperatures and mixed rain and snow the last few days, Finding any quality skiing would be a hard goal. Crusts on all aspects with the exception of shaded North above 2400m (which is likely also being affected). This would be a great time to avoid any exposure to avalanche terrain as this hot weather passes through.

Weather Summary

We are entering the big warm up of the spring. Freezing levels are going to rapidly rise to from 2900m on Wednesday to 3900m by Friday, and stay there through the weekend. This is the warm up we have been waiting for. Valley temperatures are forecasted to be in the +20 range.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be alert to conditions that change throughout the day.
  • Be alert to conditions that change with aspect and elevation.
  • Keep in mind that wet avalanches can be destructive due to their high density.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • Be aware that wet activity at low elevations is a classic situation for step-down failures in deeply buried persistent weak layers.
  • Cornices become weak with daytime heating.

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.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.