Avalanche Forecast

Archived

Feb 17th, 2023–Feb 18th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

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.

Expect avalanche hazard to rise on Sunday with incoming weather. Stay vigilant in regards to the deep persistent slab problem.

Confidence

Moderate

Avalanche Summary

Two large avalanches noted in the Maligne and Churchill Ranges in the alpine on east facing slopes on Wednesday. No Patrol on Friday.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Recent strong to extreme winds stripping exposed features and building wind slabs in the alpine and at tree line. In sheltered locations 30cm of low density snow lies over a generally weak mid and bottom snowpack with facets and depth hoar at the base. The height of snow is variable from 50 to 150cm.

Weather Summary

Saturday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -8 °C.

Ridge wind west: 15-35 km/h.

Freezing level at valley bottom.

Sunday

Flurries.

Accumulation: 11 cm.

Alpine temperature: Low -10 °C, High -6 °C.

Ridge wind west: 20 km/h gusting to 50 km/h.

Freezing level at valley bottom.

Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast

Terrain and Travel Advice

Expect slab conditions to change drastically as you move into wind exposed terrain.
Keep in mind that human triggering potential persists as natural avalanching tapers off.

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.