Avalanche Forecast

Archived

Dec 29th, 2025–Dec 30th, 2025

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, 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.

Increasing winds Tuesday afternoon could be all it takes for us to see more large Deep Persistent Slab avalanches occur.

Make conservative terrain choices and avoid overhead hazard.

Confidence

Moderate

Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.

Avalanche Summary

Numerous large, naturally triggered, Deep Persistent Slab avalanches have been observed in the past week throughout the region.

The local ski resort has also been reporting Deep Persistent Slab avalanches triggered by explosives.

Snowpack Summary

Icefields Parkway: About 50 cm of new snow fell last week, with total snow depths of 160–190 cm at TL. The upper snowpack is made up of well-consolidated storm snow from the past two weeks. A Dec facet layer sits ~60 cm above the ground, transitioning to an early-November faceting crust near the base.

Maligne Lake area: Snow depth at TL averages ~1 m and is less consolidated. The Dec facet layer is ~50 cm above the ground and closer to surface.
Widespread wind effect in all regions.

Weather Summary

Tuesday

Cloudy with sunny periods.

Precipitation: Nil.

Alpine temperature: High -5 °C.

Ridge wind southwest: 15 km/h.

Freezing level at valley bottom.

Wednesday

Mainly cloudy with isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -8 °C, High -5 °C.

Ridge wind southwest: 15 km/h.

Freezing level at valley bottom.

Thursday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: Low -8 °C, High -5 °C.

Ridge wind southwest: 15 km/h.

Freezing level at valley bottom.

Terrain and Travel Advice

Be mindful that deep instabilities are still present and have produced recent large avalanches.
Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

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.

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.