Avalanche Forecast

Issued: Dec 9th, 2021 4:11PM

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

jonas hoke,

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Skier triggering of slab and loose dry avalanches is possible. A cautious approach to large features and steep terrain is recommended.

Summary

Weather Forecast

Lingering flurries under a weak NW flow Friday will give way to a more organized system from the West into the weekend.

Friday: Flurries (up to 7 cm). Alpine High -11*C. Moderate SW ridgetop winds.

Saturday: Snow (up to 20cm). Low -13*C, High -8*C. Mod gusting Extreme SW wind.

Sunday: Flurries (up to 5cm). Low -15*C, High -11*C, Mod SW wind.

Snowpack Summary

Approximately 30 cm of new snow fell Wednesday with South winds, creating fresh slabs in exposed terrain features, and a loose dry avalanches problem in steep sheltered terrain. The Dec 1st rain crust is ~20cm thick, buried 40cm at 1300m/60cm at TL, and can be found up to 2300m. The mid and lower snowpack is generally well bonded and strong.

Avalanche Summary

On Thursday, a field team triggered two small slab avalanches on the Dec. 1st crust, these both occurred on steep slopes at treeline.

On Wednesday several large avalanches were observed above the highway. The majority of these were in very steep terrain off of Mt Macdonald and Tupper.

Confidence

Due to the number and quality of field observations

Problems

Loose Dry

An icon showing Loose Dry

Expect sluffing/loose dry avalanches in steep unsupported terrain features.

  • Use caution above cliffs and terrain traps where small slab avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs

With lots of snow available for transport windslabs will continue to grow with any wind inputs.

  • Use caution in alpine and open treeline lees. Recent snowfall has created slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

There is now 50-90cm on the Dec. 1st crust, which is just beginning to gain enough cohesion to fail as a slab.

  • Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Dec 10th, 2021 4:00PM