Avalanche Forecast

Archived

Mar 19th, 2025–Mar 20th, 2025

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 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.

A substantial amount of snow has accumulated over a weak underlying snowpack. Large avalanches have been reported in the forecast region and remote triggering is a significant concern. Stick to low angle terrain well away from steeper slopes.

Confidence

Moderate

Snowpack Summary

Wind slab development March 18th and 19th at tree line and above. Storms on March 9th and March 13th brought 70-90 cm which is settling and creating a supportive midpack. Below this new load, the snowpack is complicated and reactive, having multiple crusts and facet layers including the deep persistent basal layer.

Weather Summary

Overnight: Mainly cloudy with isolated flurries. Precipitation: Trace. Alpine temperature: Low -7 °C. Ridge top wind southwest: 15-35 km/h.Thursday: Cloudy with sunny periods and isolated flurries. Precipitation: Trace. Alpine temperature: High -4 °C. Wind: 15-35 km/h. Freezing level: 1600 meters.

Friday: Flurries: 7 cm. Alpine temperature: Low -8 °C, High -6 °C. Wind: 15 km/h gusting to 60 km/h.

Terrain and Travel Advice

Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Make conservative terrain choices and avoid overhead hazard.

Problems

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.

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.