Avalanche Forecast

Archived

Feb 15th, 2020–Feb 16th, 2020

Alpine

Natural avalanches possible, human triggered probable.

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, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis.

Despite strong west winds over the past few days at upper elevations, we are still finding good skiing in sheltered areas. Expect to encounter windslabs along ridgelines and crossloaded features up to 40cm thick.

Confidence

High -

Weather Forecast

Pretty stable weather the next few days. Flurries will continue with max accumulations around 10cm. Winds will begin to get more light to moderate out of the NW and temperatures will be in the -10C range. Pretty much a mix of sun and cloud in the sky. No big storms on the horizon.....

Avalanche Summary

No new slab avalanches were observed. A few new loose dry avalanches out of steep unskiable terrain up to sz 1 were observed.

Snowpack Summary

An additional 10cm has fallen over the past 24hrs bringing recent totals up to 20cm in Alpine areas. Winds have been variable and as a result, windslabs up 40cm are being found in alpine areas along ridgelines and crossloaded gully features. Some isolated cracking was observed, in steeper unsupported areas. Despite no recent activity, the basal layers are still constantly in our minds. Thin weak areas are likely trigger points for initiation on this interface.

Terrain and Travel

Use ridges or ribs to avoid areas of wind loaded snow.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Avoid travelling on slopes below cornices.
Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Be mindful that deep instabilities are still present and have produced recent large avalanches.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

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.

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.