Avalanche Forecast

Archived

Mar 5th, 2023–Mar 6th, 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 possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential while waiting out the deep persistent instabilities.Thin to thick areas are the most likely skier trigger points.

Confidence

Moderate

Avalanche Summary

A number of large avalanches up to size 3 were observed last week. Natural activity has tapered off since but the snowpack is very sensitive to small inputs of new snow, loading, and changes in temperature. Large avalanches mostly initiate from the alpine but have a potential to run through all elevation bands.

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

Snowpack Summary

Top 20 to 40cm of low density facetted crystals in sheltered areas. There is extensive wind effect at tree line and above from previous SW winds with a dash of reverse loading happening from the recent light easterly winds.

This is sitting on top of a generally weak mid and lower snowpack. Facets and depth hoar linger at the base of the snowpack with the height of snow varying from 60 to 160cm.

Weather Summary

Monday and Tuesday forecast is calling for cold temperatures and light winds. Alpine highs around -10C to -15C. Freezing level at valley bottom.

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

Terrain and Travel Advice

If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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.