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Avalanche Forecast

Archived

Dec 20th, 2022–Dec 21st, 2022

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, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Banff Yoho Kootenay, Little Yoho, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N.

The snowpack is shallow, weak and faceted. Human triggering remains possible. Extreme cold temperatures will exacerbate the consequences of being caught in an avalanche, an injury, or a gear malfunction.

Confidence

Moderate

Avalanche Summary

No avalanches were observed or reported on Tuesday.

Snowpack Summary

The snowpack is shallow and weak with a base of facets and depth hoar. A 20-60 cm slab overlies this weak base and could easily be triggered in some locations. Loose, faceted sluffs are being triggered below treeline in some locations and any avalanches that do release will run further than expected with the cohesion-less snow.

Weather Summary

Bitter cold with lows close to -40 on Wednesday. Thankfully the wind will remain light and variable. A warming trend with some snow is expected over the weekend.

Terrain and Travel Advice

  • Uncertainty is best managed through conservative terrain choices at this time.

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.