Avalanche Forecast

Archived

Feb 8th, 2023–Feb 9th, 2023

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Fryatt, Maligne, Marmot, Miette Lake, Pyramid.

North and eastern parts of the Jasper bulletin region saw significantly less precipitation than the Icefields area.

Confidence

Moderate

Avalanche Summary

One large avalanche occurred in the alpine on an east facing slope in the Churchill range on Wednesday.

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

Snowpack Summary

Up to 7cm of new snow out of the recent storm. Previous moderate to strong southwest wind stripped snow in exposed alpine features creating wind slab in the alpine and into exposed tree line. A weak melt freeze crust facet combo down 25cm below 2100m is showing sudden collapse results in snow pit tests. Generally, the bottom of the snowpack is weak facets and depth hoar. The snowpack ranges from 50 to 120cm.

Weather Summary

Thursday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: High -3 °C.

Ridge wind southwest: 40-50 km/h.

Freezing level: 1300 metres.

Friday

A mix of sun and cloud with isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -8 °C, High -5 °C.

Ridge wind southwest: 35 km/h gusting to 60 km/h.

Freezing level: 1300 metres.

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

Terrain and Travel Advice

In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

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.

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.