Avalanche Forecast

Archived

Feb 4th, 2024–Feb 5th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

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

A hard crust on the surface may feel impenetrable at lower elevations but our persistent / deep persistent problems continue to linger in the mid and lower snowpack. Triggering these persistent layers is most likely in areas where the crust is weak or deteriorating.

Confidence

Moderate

Avalanche Summary

No new avalanche activity has been observed or reported on the Icefields Parkway or Maligne Lake Road since Friday.

Previous widespread avalanche activity last week produced numerous natural avalanches at all elevations. This included some impressive avalanches up to size 3.5 at higher elevations, as well as loose wet up to size 2.

Snowpack Summary

A 1-6 cm crust exists up to 2500m. A sun crust can be found on solar aspects to mountain top.

Persistent weak layers, formed in early January, are down 20-30cm in sheltered areas. The bottom of the snowpack is made up of well-developed facets and depth hoar creating our deep persistent problem.

Weather Summary

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

Monday Mainly cloudy with isolated flurries. Trace precipitation. Alpine High -5 °C. Light wind. Freezing level valley bottom

Tuesday Cloudy with scattered flurries. Accumulation: 4 cm. High -3. Wind SW 10-25 km/h. Freezing level 1800m

Wednesday Sun/cloud & isolated flurries. Trace precipitation

Terrain and Travel Advice

Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
This avalanche problem is difficult to trigger but if so, consequences are serious.

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.

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.