Avalanche Forecast

Archived

Nov 22nd, 2021–Nov 23rd, 2021

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper.

Warmer temperatures, high humidity, moderate to strong winds and new snow are a good recipe for new windslab development.

Weather Forecast

Tonight: Flurries.

Accumulation: 6 cm.

Alpine temperature: Low -7 C.

Ridge wind SW: 15 km/h gusting to 50 km/h.

Tuesday: Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -6 C.

Ridge wind W: 10-25 km/h.

Snowpack Summary

Strong SW winds stripped all aspects in the alpine. New snow with warm temperatures and moderate winds will likely create new wind slabs. Above freezing temperature to 1700m will likely result in a future crust. A 1-2cm thick crust 80cm down is found up to 2500m or higher. Below this crust are more crusts or facets depending on elevation.

Avalanche Summary

No new avalanches were observed on Monday.

Confidence

Due to the number and quality of field observations

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.

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.