Avalanche Forecast

Archived

Jan 13th, 2023–Jan 14th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

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.

Regions

Jasper, Churchill, Cirrus-Wilson, Fryatt, Icefields, Miette Lake.

Cornice failures on east aspects were triggering large avalanches on Friday. Watch for this to continue as long as the freezing level remains high.

Confidence

Moderate

Avalanche Summary

A field team went to Parker Ridge today. Significant large avalanche activity were observed mostly on east aspects as the result of falling cornices. Most of these avalanches were stepping down to ground.

If you're out in the hills, don't forget to post to the MIN. Every bit of information helps!

Snowpack Summary

5cm of new snow with strong to extreme SW winds in the alpine on Friday. Freezing levels around Parker Ridge were around 2200m likely creating moist snow on the surface. A layer of surface hoar and facets is down 20-40cm in sheltered areas. Large facets and depth hoar comprise the bottom portion of the snowpack. Snowpack depths vary from 50-100cm.

Weather Summary

Saturday

Mainly cloudy with isolated flurries.

Precipitation: Trace.

Alpine temperature: High -3 °C.

Ridge wind southwest: 10-25 km/h.

Freezing level: 1800 metres.

Sunday

Cloudy with sunny periods.

Precipitation: Nil.

Alpine temperature: Low -10 °C, High -6 °C.

Light ridge wind.

Freezing level at valley bottom.

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

Terrain and Travel Advice

Make conservative terrain choices and avoid overhead hazard.
Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
Caution around slopes that are exposed to cornices overhead.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.