Avalanche Forecast

Archived

Feb 28th, 2024–Feb 29th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

This storm is causing rapid loading on an already unstable snowpack. Avoid avalanche terrain as a natural avalanche cycle is expected.

The Icefields Parkway is CLOSED for avalanche hazard and control. Check Alberta 511 for updates.

Confidence

Moderate

Avalanche Summary

A widespread natural avalanche cycle is expected on Thursday.

Snowpack Summary

Up to 50 cm of new snow is expected to fall in this storm with strong southwest winds. This new snow is falling on 15 to 50 cm of previous storm snow that had widespread windslab development. Both storms are now sitting on faceted snow above a 1-3cm thick crust that is down 35-80 cm. The mid-pack is faceted with basal depth hoar and well developed facets near ground. HS ranges from 80 to 130cm.

Weather Summary

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

Thursday

Flurries, 5-10cm. Alpine temperature: High -5 °C. Freezing level at valley bottom. Ridge wind southwest 15 km/h, gusting to 50 km/h.

Friday

Mainly cloudy with isolated flurries. Alpine temperature: Low -16 °C, High -11 °C. Freezing level at valley bottom. Ridge wind south: 10-25 km/h.

Terrain and Travel Advice

Only the most simple non-avalanche terrain free of overhead hazard is appropriate at this time.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.