Avalanche Forecast

Archived

Jan 12th, 2023–Jan 13th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

The incoming storm will increase avalanche hazard. Keep it conservative.

Confidence

Moderate

Avalanche Summary

A field team went up to Maligne today. No significant avalanche activity has been observed or reported.

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

Snowpack Summary

Increasing winds and up to 15mm of new snow is expected to start Thursday evening. This new snow will be covering surface hoar from Jan 7th in specific sheltered areas. Another 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

Friday

Cloudy with scattered flurries.

Accumulation: 5 cm.

Alpine temperature: High -1 °C.

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

Freezing level: 2100 metres.

Saturday

Mainly cloudy with isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -5 °C, High -3 °C.

Ridge wind southwest: 10-30 km/h.

Freezing level: 1700 metres.

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

Terrain and Travel Advice

Make conservative terrain choices and avoid overhead hazard.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.