Avalanche Forecast

Archived

Mar 3rd, 2023–Mar 4th, 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.

The strong winds are easing off, and with that natural avalanche activity will as well.

Don't be lolled into complacency though, large destructive avalanches, especially human triggered ones, are still possible.

Confidence

Moderate

Avalanche Summary

A number of large avalanches up to size 3 have been observed and reported over the week. The snowpack is very sensitive to small inputs of new snow, loading, and changes in temperature. These avalanches are mostly from the alpine but are running through all elevation bands.

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

Snowpack Summary

5 to 15cm of new snow since March 1st overlies 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.

The upper snowpack consists of 30-50 cm of settled snow or wind slab 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

Saturday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -12 °C.

Ridge wind east: 10-30 km/h.

Freezing level at valley bottom.

Sunday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: Low -25 °C, High -15 °C.

Ridge wind southeast: 10 km/h.

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.

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.