Avalanche Forecast

Issued: Jan 1st, 2022 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Expect fresh wind slabs forming throughout the day to elevate avalanche danger as the next storm blows in. Also check out the latest Forecasters' Blog for tips on managing the persistent slab problem in this region.

Summary

Confidence

Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.

Weather Forecast

Saturday night: Partly cloudy. Moderate to strong southwest wind. Alpine temperature around -15 C.

Sunday: A mix of sun and cloud with flurries starting in the afternoon bringing a trace of new snow. Moderate to strong southwest wind. Alpine high of -10.

Monday: Around 5 cm new snow for most areas, up to 20 cm in the west of the region. Moderate southwest wind. High of -5 C.

Tuesday: 5-10 cm new snow. Light southwest wind. High of -15 C.

Avalanche Summary

Wind slabs have been reactive in recent days.

On Friday, explosive control work produced a size 2.5 (large) wind slab avalanche that stepped down to the persistent slab layer on a southeast aspect around treeline.

Wind slabs were touchy on Thursday when natural and remotely triggered size 2 wind slab avalanches were reported on easterly aspects at alpine and treeline elevations.

Explosive control work on Wednesday produced numerous size 3 wind slab avalanches in the alpine on primarily northwest aspects.

Snowpack Summary

Snow surfaces at upper elevations are generally wind affected, the extent of wind effect variable throughout the region with hard slabs especially prevalent in the south.

The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 50-120 cm. In the past week, we have seen explosive triggered activity on this layer as well as snowpack tests that have shown moderate results. This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.

Terrain and Travel

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Fresh wind slabs are likely to form at upper elevations as strong winds precede the next storm. Lingering reactivity may also be observed in older wind slabs on a variety of aspects.

Aspects: North, North East, East, South East, South, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A persistent slab problem formed by a crust down 60-100 cm has created a low likelihood, high consequence scenario that is difficult to forecast. Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 2nd, 2022 4:00PM

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