Avalanche Forecast

Archived

Mar 11th, 2023–Mar 12th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

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.

Solar effect has been less influential than originally forecast and the snowpack structure has changed very little over the past week. The hazard remains moderate in the alpine and at treeline due to uncertainty regarding the reactivity of our deep persistent slab problem.

Shaded, polar slopes will have better skiing at treeline and below.

Confidence

Moderate

Avalanche Summary

Avalanche control using explosives on Hwy 93N resulted in few wind slabs and numerous loose dry avalanches up to size 2 on Wednesday, March 8.

No new natural avalanche activity observed on Maligne Road or Icefields Parkway today.

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

Snowpack Summary

A weak sun crust can be found on sun-exposed slopes at lower elevations. Wind sheltered areas and sun-protected slopes have 20 to 40cm of low density facetted snow. There is extensive wind effect at tree line and above from previous SW winds.

The mid and lower snowpack is generally weak and faceted with depth hoar lingering at the base. Snowpack depth varies from 60 to 160cm.

Weather Summary

Sunday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -8 °C.

Ridge wind southwest: 10-25 km/h.

Freezing level at valley bottom.

Monday

Snow.

Accumulation: 17 cm.

Alpine temperature: Low -8 °C, High -3 °C.

Ridge wind southwest: 15-35 km/h.

Freezing level rising to 1700 metres.

Tuesday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -17 °C, High -10 °C.

Ridge wind southwest: 15 km/h gusting to 40 km/h.

Freezing level at valley bottom.

Freezing level rising to 1600 metres.

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.