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Archived

Avalanche Forecast

Dec 21st, 2023–Dec 22nd, 2023
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
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
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
2: Moderate
The avalanche danger rating in the alpine will be moderate
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

Choose conservative terrain and give the storm snow time to bond.

Fresh snow and increasing winds are further burying a concerning layer of surface hoar.

Confidence

Moderate

Avalanche Summary

Poor visibility has limited observations. We have received reports of debris from large avalanches in run outs at lower elevations. Likely storm slabs starting in the alpine.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

Up to 30 cm of new dense snow has buried a variety of previously wind-affected surfaces.

A concerning surface hoar layer is roughly 40 to 70 cm below the surface.

The mid snowpack likely contains multiple frozen crusts, while the lower snowpack is generally faceted. Average snowpack depths at treeline range from 50 to 100 cm.

Weather Summary

Thursday Night

Cloudy with up to 15 cm of new snow expected, southwest alpine wind 50 to 80 km/h, freezing level around 2000 m.

Friday

Mostly cloudy with around 5 cm of new snow expected, southwest alpine wind decreasing to 30 to 60 km/h, freezing level falling to valley bottom.

Saturday

Clearing throughout the day with trace amounts of new snow expected, west alpine wind 20 to 40 km/h, treeline temperature -7 °C.

Sunday

Mostly cloudy with no new snow expected, southwest alpine wind 40 to 70 km/h, freezing level rising to 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Choose conservative terrain and watch for clues of instability.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

Avalanche Problems

Persistent Slabs

Buried surface hoar layers will become more concerning as new snow accumulates and forms cohesive slabs above.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5

Storm Slabs

As new snow continues to accumulate, surface slabs will increase in size and reactivity. Deeper deposits of cohesive snow will be likely in leeward terrain features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5