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Archived

Avalanche Forecast

Nov 28th, 2021–Nov 29th, 2021
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

If you find a crust forming on the surface today, avalanches will be unlikely. However without significant cooling, the upper snowpack will likely remain wet and punchy with the potential for human triggered loose wet avalanches.

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

As the snowfall tapers Sunday night, we'll see a brief break Monday before yet another storm arrives Tuesday.

Sunday night: Flurries, 5-10mm tapering by morning. Wind easing to moderate and shifting west. Freezing level 1800 m.

Monday: Mostly cloudy. Light westerly wind. Alpine temperature around -2 C. Freezing level 1700m.

Tuesday: Around 10 cm new snow. Strong southwest wind. Freezing level 1600 m. 

Wednesday: Around 10 cm new snow turning to rain. Strong southwest wind. Freezing level rising to 2500 m.

Avalanche Summary

We have not received any observations from the weekend's storm.

On Friday, minor avalanche cycle size 1-2 was observed on north facing alpine start zones. A size 1.5 skier accidental storm slab was reported on the Mountain Information Network near Nelson. They noted a fast moving avalanche with wide propagation, supported by a hard bed surface.

Note that there are very few field observations in the Kootenay Boundary this early in the season. Backcountry users need skills in assessing conditions and decision making. If you go out in the mountains, please share your observations and/or photos on the Mountain Information Network!

Snowpack Summary

The upper snowpack consists of moist, dense snow, settling quickly in the warm temperatures. In the Okanagan a 2mm rain crust may exist at the interface between recent storms.

The mid-November crust is down 25-50 cm and is up to 10 cm thick. The lower snowpack is a series of crust and facet layers. At the bottom of the snowpack, up to 20 cm of faceted snow may be found. 

Snowpack depths at treeline range from 40-100 cm, with alpine depths exceeding 150 cm in areas. Below 1700m, snowpack depths decrease rapidly.

Terrain and Travel

  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • A crust on the surface will help bind the snow together, but may make for tough travel conditions.

Avalanche Problems

Loose Wet

If you find a crust on the surface, avalanches will be unlikely. However, without significant cooling in sight, the upper snowpack will likely remain wet and punchy, with the potential for human triggered loose wet avalanches.

 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1.5 - 2.5