Avalanche Forecast

Archived

Dec 28th, 2021–Dec 29th, 2021

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Banff Yoho Kootenay.

Some great skiing to be had for those who brave the cold! If you go, remember to pack extra layers, choose short objectives close to the road, and be prepared to survive the cold if something goes wrong.

Weather Forecast

A generally stable weather pattern for the next 3 days. Daytime highs will be ~ -20 C and overnight lows ~ -30 C. A weak system moves through Wednesday afternoon/ overnight with increased alpine winds and a few centimetres of snow. Otherwise, clear skies, cold temperatures and light winds dominate.

Snowpack Summary

10-40 cm of snow last week with wind from various directions has developed small wind slabs mainly in the alpine but also in isolated treeline areas. There is 50-70 cm over the Dec 2 crust/facet combo which exists below 2200m. This has not been an active problem yet but we are monitoring it closely. Shallow areas (<100 cm) have weaker basal facets

Avalanche Summary

A couple size 1 loose dry natural avalanches were observed on Tuesday in steep alpine terrain. These were primarily from steep, rocky, thin snowpack areas and likely a result of the cold temperatures facetting the snowpack. Local ski areas were able to trigger small wind slabs in lee areas in the alpine with ski cuts and explosives.

Confidence

Due to the number of field observations

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.