Avalanche Forecast

Archived

Dec 7th, 2023–Dec 8th, 2023

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 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, human triggered possible.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Icefields.

The snowpack is still adjusting to the load from this week's storm and is structurally weak. Make conservative decisions until the new snow has had time to settle and stabilize.

Good skiing is out there but the threat of early season hazards is real and just below the surface. Read a recent report from Parkers here.

Confidence

Moderate

Avalanche Summary

Numerous storm slab avalanches released during Tuesday's storm, failing on the Dec 2 surface hoar, facet and melt-freeze crust layer.

More information on a size 1.5 near Parkers ridge behind Hilda hostel can be found here (Here).

Snowpack Summary

30cm of new snow from this week's storm has formed a persistent slab and windslab where it has been redistributed by strong winds. This overlies a weak surface hoar and facet layer or a melt-freeze crust on south and west aspects. The snowpack is 35-45cm in depth with a weak facetted base.

A rain crust exists below 1800m.

Weather Summary

The Mountain Weather Forecast is available from Avalanche Canada https://avalanche.ca/weather/forecast

Friday

Cloudy with sunny periods. Ridgetop westerly winds 10-20 km/h.

Alpine temperature: High -9 °C.

Saturday

Cloudy with sunny periods and isolated flurries bringing a trace amount of snow. Ridgetop wind southwest 20-35 km/h.

Alpine temperature: Low -16 °C, High -13 °C.

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Don't let the desire for deep powder pull you into high consequence terrain.

Problems

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.