Avalanche Forecast

Issued: Feb 20th, 2020 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Deep Persistent Slabs.

Parks Canada mark herbison, Parks Canada

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Avoid terrain features that are/or have been loaded by alpine winds. Investigate snow depths as you travel through terrain and avoid committing yourself to shallow snowpack areas where the deep persistent layer could be triggered.

Summary

Weather Forecast

Friday will be mainly cloudy with isolated flurries and periods of sun. The temperature inversion is forecasted to weaken with an alpine high of -9. The winds will remain moderate to strong from the SW. 5-10cm of snow is forecasted throughout the day on Saturday.

Snowpack Summary

Fresh wind  slab development and continued cornice growth today in the alpine. Sun crust formation on steep S and SW facing terrain. Weak, facetted snow near the base of the snowpack persists in much of the range, producing isolated but large avalanches.

Avalanche Summary

Reports of wind slabs up to size 1.5 today along the Icefields Parkway in loaded pockets in the alpine.

A size 2.5 skier remote was reported Wednesday on the scramblers route of Cascade Mountain on a steep SW slope in the alpine, no involvement.

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs

Consistent moderate winds from the SW have formed fresh wind slab in the alpine. Cornices have grown very large in recent weeks, so watch your exposure to them carefully.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Several large avalanches failing naturally on the basal facet/depth hoar have been observed in the past week. These are hard to predict, but are most likely in areas with a thin snowpack (~150cm) where the basal facets and depth hoar are prominent.

  • Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3.5

Valid until: Feb 21st, 2020 4:00PM

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