Avalanche Forecast

Archived

Jan 5th, 2022–Jan 6th, 2022

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper.

Pay attention to snowfall amounts and increasing winds throughout the day on Thursday. These inputs can increase avalanche danger.

Weather Forecast

Thursday

Cloudy with scattered flurries.

Accumulation: 5 cm.

Alpine temperature: High -11 °C.

Ridge wind southwest: 10-20 km/h.

Freezing level at valley bottom.

Friday

Cloudy with scattered flurries.

Accumulation: 5 cm.

Alpine temperature: Low -19 °C, High -7 °C.

Ridge wind southwest: 15-35 km/h.

Freezing level at valley bottom.

Snowpack Summary

Cold temperatures continue to promote faceting. Expect lingering wind slabs in deposition zones. The mid-pack is supportive with the Dec 1st interface down 40cm as a rain crust below 1950m. Basal faceting continues near or on the ground.

Avalanche Summary

One large avalanche was reported by the public over an ice climb on Mt. Wilson. See the MIN report.

Confidence

Forecast snowfall amounts are uncertain on Friday

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.