Avalanche Forecast

Archived

Dec 20th, 2023–Dec 21st, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

Ice Climbers: What's over your head?

Warm temps over the next few days will make thin, early-season ice even weaker.

Watch for isolated slabs, loose dry, and sluffs in consequential terrain.

Riders: If you find the snowpack supportive, you are on a slab over weak facets, it's not a great combo.

Best bet for safe turns, try the ski hill.

Confidence

High

Avalanche Summary

Following a weak weather system from Monday, there was ~10mm of precip. Now, it has been well redistributed in open terrain around the Icefields. The whole area is in rough shape. The alpine is stripped to only the immediate lee features throughout the Icefields and Mt Wilson zones. Deep facet wallowing should be expected on alpine ice approaches. Coming new snow for Friday is only likely to hide surface hazards.

Snowpack Summary

The snowpack is 45-80cm deep and is cold, weak, and facetted. Strong winds have stripped exposed alpine and tree-line terrain, creating hard wind slabs in cross-loaded and lee features. Basal weakness is a combo of large facets and chains of depth hoar.

Weather Summary

The Mountain Weather Forecast is available at Avalanche Canada https://avalanche.ca/weather/forecast

Thursday at the Icefields

Mainly cloudy. No precip. Alpine High of -1 °C. Moderate to light SW ridgetop winds.

Freezing levels are high. Warm temps. at TL and BTL. Especially around Jasper townsite.

Terrain and Travel Advice

Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.
Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.

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.