Avalanche Forecast

Archived

Apr 5th, 2023–Apr 6th, 2023

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, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Last day with a good previous overnight freeze on Thursday before the weather changes. Use caution on solar aspects and at lower elevations if the snowpack warms up faster than expected. The wind has also been back at work, moving snow into thin wind slabs at tree line and above.

Confidence

Moderate

Avalanche Summary

Only isolated small loose dry avalanches in steep alpine terrain have been observed in the region in the last few days.

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

Snowpack Summary

Moderate to strong winds have redistributed the dusting of new snow from last week. Under this there is a sun crust at all elevations on solar aspects, with mixed facets on polar aspects. The mid-pack consists of multiple layers of dense wind effected snow, sun crusts, and facets. Depth hoar and basal facets make up the base of the snowpack. Snow depth varies ranges from 60-170cm.

Weather Summary

On Thursday mainly sunny conditions with increasing cloudiness by the afternoon, and Southwesterly ridgetop winds 30-40 km/h. Freezing levels will rise to between 1800 and 2000 m, with an alpine high of -3°C. On Friday an increasingly robust southwesterly upper level flow will move in with increasing winds, rising temperatures, and some light precipitation.

Terrain and Travel Advice

Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.