Avalanche Forecast

Archived

Feb 3rd, 2023–Feb 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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

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

Strong winds continue to build wind slab at treeline and above. Watch for wind slab development farther down slopes than usual.

Confidence

Moderate

Avalanche Summary

One skier triggered size 1 avalanche occurred in the Buck Lake area of the Icefields Parkways on Jan 31st.

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

Snowpack Summary

Strong southwest wind is stripping snow in exposed alpine features and creating wind slab into exposed tree line. A thin melt freeze crust down 25cm below 2100m is showing sudden collapse results in snow pit tests below this layer on facets. Generally, the bottom of the snowpack is weak facets and depth hoar. The snowpack ranges from 50 to 120cm.

Weather Summary

Saturday- Mainly cloudy with isolated flurries.

Precipitation: Trace.

Alpine temperature: High -6 °C.

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

Freezing level: 1400 metres.

Sunday- Mainly cloudy with scattered flurries.

Accumulation: 4 cm.

Alpine temperature: Low -9 °C, High -5 °C.

Ridge wind southwest: 20 km/h gusting to 50 km/h.

Freezing level: 1500 metres.

Monday-Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -14 °C, High -9 °C.

Ridge wind southwest: 20-40 km/h.

Freezing level at valley bottom

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.
Watch for signs of slab formation throughout the day.

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.