Avalanche Forecast

Archived

Mar 8th, 2025–Mar 9th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

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.

The Icefields Parkway is closed due to elevated avalanche hazard until avalanche control and snow removal can be completed.

Check for updates on Alberta 511

It is best to avoid all avalanche terrain until this storm is over.

Confidence

Moderate

Avalanche Summary

Two large naturally occurring Deep Persistent Slabs were observed in the backcountry adjacent to the ski hill on March 7th.

Snowpack Summary

Up to 10cm of new snow and strong westerly winds during the day on Saturday. The top 20-40cm of the snowpack is complex, with multiple crusts and facet layers depending on location. Within the upper 60 cm of the snowpack there are two more persistent weak layers of a similar structure. The bottom of the snowpack is generally weak facets and depth hoar.

Weather Summary

Saturday Night

Periods of snow.

Accumulation: 18 cm.

Alpine temperature: Low -5 °C.

Ridge wind southwest: 20 km/h gusting to 65 km/h.

Sunday

Snow.

Accumulation: 20 cm.

Alpine temperature: High -4 °C.

Ridge wind southwest: 20 km/h gusting to 65 km/h.

Monday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -14 °C, High -9 °C.

Ridge wind west: 15-35 km/h.

Terrain and Travel Advice

Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.