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Avalanche Forecast

Dec 31st, 2019–Jan 1st, 2020
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Lizard-Flathead.

A juicy storm is expected to bring enough snow to result in natural avalanches in steep mountain terrain. I recommend sticking to forested slopes (skiers) or low-angled meadows (sledders) as the best way to welcome in the New Year under current conditions.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Tuesday night: 20-25 cm of snow, strong wind from the southwest, alpine low around -6 C.Wednesday: Another 10-20 cm of snow by noon then cloudy in the pm, moderate wind from the west, alpine high temperature around -1 C, freezing level 1500 m.Thursday: Scattered flurries accumulating up to 5 cm, moderate wind from the west, alpine temperature dropping to -5 C.Friday: Scattered flurries accumulating up to 5 cm, moderate wind from the southwest, alpine high temperature rising to +1 C, freezing level rising to 2000 m.

Avalanche Summary

It's now been a week since a widespread cycle of very large deep persistent slab avalanches occurred in response to the storms prior to Christmas, and four days since this avalanche was reported north of Fernie in the neighbouring South Rockies region. Full depth avalanches might still occur under one of the following scenarios: the weather forecast is dramatically wrong and we end up with far more new snow than expected; or from human-triggering in a thin, rocky start zone.

Thin wind slabs, which still could be nasty in steep exposed terrain, or if there is a terrain trap like a cliff, should be expected with the forecast incoming weather.

Snowpack Summary

New snow and wind are generating fresh wind slabs in exposed locations. Sheltered terrain currently has 20-40 cm of soft snow. Below 1700 m a hard rain crust is becoming buried and may still make for difficult travel. Hard snow sits above weak snow and crusts near the bottom of the snowpack (80-150 cm deep).This weak snowpack structure resulted in very large avalanches prior to Christmas. The likelihood of triggering a deep persistent slab avalanche has declined since then, but could still be possible from thin spots in steep terrain that did not avalanche in the last storm.

Terrain and Travel

  • Avoid all avalanche terrain during periods of heavy snowfall.
  • Watch for fresh storm slabs building throughout the day.