Avalanche Forecast

Issued: Dec 22nd, 2020 4:00PM

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

Darren vonk,

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Ice climbers beware, Many avalanches, both loose dry and wind slabs were directly observed failing today on Mt Wilson. Even a small sluff can be bad news in a terrain trap.

Summary

Weather Forecast

A mix of sun and cloud for the next several days.

Winds will be generally light out of the West with cool nights -16 and seasonable temps -10 during the day.

No new snow expected.

Snowpack Summary

The snowpack continues to settle rapidly. NW winds continue to strip recently loaded lee slopes and build wind slabs in S-SE features. Decomposing surface hoar down 30cm to 50cm in sheltered locations treeline and below. The midpack is generally supportive with a weaker base consisting of facets and depth hoar. Avg depth is 65cm - 160cm depending

Avalanche Summary

A road patrol down to Saskatchewan crossing noted numerous wind slabs to size 2.5 out of West facing alpine features on Mt. Wilson along with several loose dry avalanches to Size 2 on west facing steep terrain. Back towards the Icefields, 3 Size 2 fresh wind slabs from reverse loading in the alpine were noted today.

Confidence

Due to the quality of field observations

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate NW winds have stripped previously loaded slopes and reverse loaded S-SE slopes in the Alpine and open Tree line. Caution as these freshly built wind slabs are reactive naturally in the alpine.

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Be careful with reverse loaded pockets of wind slab at ridgeline.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Loose Dry

An icon showing Loose Dry

Numerous dry loose avalanches up to size 2 out of steep alpine terrain noted today on Mt.Wilson, Heads up climbers, There is a lot of overhead above you at the moment.

  • Minimize exposure to terrain traps where the consequences of an avalanche could be serious.
  • Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Be cautious of thick to thin snowpack areas being likely trigger locations. The wind slabs have the potential to step down to the weakness at the base of the snowpack.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Use caution in thin snowpack areas.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Dec 23rd, 2020 4:00PM

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