Avalanche Forecast

Issued: Nov 23rd, 2023 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is early season. Known problems include Persistent Slabs.

SH, Avalanche Canada

Banff Yoho Kootenay, Banff, East Side 93N, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N, Field, Little Yoho.

There is some new snow in Eastern regions but no change overall. We are still operating with few field observations, but in steep terrain with enough snow, watch for slabs sitting over a weak base.

Early Season Conditions mean high variability right now.

Summary

Confidence

Moderate

Avalanche Summary

A natural size 2.5 avalanche on Redoubt Bowl in the Lake Louise backcountry was observed. This happened within the last 36 hours and slid on the October crust. Today at Sunshine ski area, a size 1.5 persistent slab was triggered by a small sluff in cliffy terrain.

Snowpack Summary

An upslope storm lay down 30+ cm in Eastern regions like Norquay, 20cm in Banff and Sunshine ski area, and much less along hwy. 93 North and Yoho. This new snow overlies alpine and treeline areas that were previously scoured by strong SW winds, and a melt-freeze crust from recent solar input on south and west aspects. The bottom of the snowpack consists of a buried crust (Oct. 23) and facets. 30-50 cm exists at treeline and 40-80 cm in the alpine.

Weather Summary

High pressure will sprawl across the region on Friday. Mainly sunny skies and light northerly winds at ridgetop are anticipated. Temperatures will be cooler, with lows in the -13 to -18C range. This pattern will continue for the next few days.

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Terrain and Travel Advice

Ice climbers should be equipped with avalanche safety gear.
Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

Problems

Persistent Slabs

Many places with enough snow to avalanche have a weak layer of facets and/or a melt freeze crust at the base of the snowpack. This layer has become less sensitive, but can still be triggered.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Nov 24th, 2023 4:00PM