Avalanche Forecast

Archived

Dec 24th, 2022–Dec 25th, 2022

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

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, human triggered possible.

Regions

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

Incremental loading from a building wind slab problem is the first significant test of our weak, faceted, snowpack. The snowpack has undergone a substantial change and should be reassessed with a cautious attitude.

Travelers and recreationalists should be aware of the potential for intermittent Road Closures on the Icefields Parkway (93N) on Dec 25 or 26th. Check AB511 for live updates.

Confidence

Moderate

Avalanche Summary

Poor visibility limited observations on the icefields parkway Saturday. Park staff reported intense wind transport beginning in the afternoon with heavy drifting at roadside.

Please consider submitting a MIN report if you are heading out for some holiday fun!

Snowpack Summary

10-20cm of new snow has created fresh wind slabs. These new wind slabs sit over a heavily faceted midpack created during our recent deep freeze. The bottom of the snowpack is weak consisting of basal facets with pockets of depth hoar. The snowpack height ranges from 50-120cm. Snowpack is unsupportive tree line and below.

Weather Summary

Sunday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -7 °C.

Ridge wind southwest: 15 km/h gusting to 40 km/h.

Freezing level at valley bottom.

Monday

Periods of snow.

Accumulation: 14 cm.

Alpine temperature: Low -6 °C, High -3 °C.

Ridge wind southwest: 25 km/h gusting to 70 km/h.

Freezing level: 1700 metres.

Tuesday

Cloudy with scattered flurries.

Accumulation: 4 cm.

Alpine temperature: Low -8 °C, High -3 °C.

Mostly light ridge wind occasionally gusting to 40 km/h.

Freezing level: 1500 metres.

Terrain and Travel Advice

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

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.

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.