Avalanche Forecast

Archived

Dec 23rd, 2021–Dec 24th, 2021

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

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.

Regions

Jasper.

Hwy 93 is closed - avalanche control is planned for Friday December 24 with estimated opening 1800hrs. Call or click 511 for details.

New wind slab and extreme cold temps should be on your mind when you venture out.

Weather Forecast

Precipitation and winds will taper off Thursday night as the Arctic high settles in.

Friday

Isolated flurries

Accumulation: trace

Alpine temperature: High -19 C.

Ridge wind light.

Freezing level at valley bottom.

Saturday

Flurries.

Accumulation: 4 cm.

Alpine temperature: Low -31 C, High -24 C.

Ridge wind light east.

Clearing Sunday with more extreme cold.

Snowpack Summary

20-35cm (25mm) low density storm snow over the past 48 hrs accompanied by moderate to strong SW winds adding to wind slab development in the alpine and on exposed terrain features at treeline. The mid-pack is supportive with a weak rain crust up to 1950m. Cold temperatures and a crust/facet layer near the base continues to promote basal faceting.

Avalanche Summary

Limited visibility icefields area - one size 2 deep persistent 1m deep by 75m wide observed likely triggered by cornice N alpine feature; a few wind slabs noted to size 1.5 northerly aspects alpine; numerous dry loose to size 1.5 all elev

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Confidence

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.