Avalanche Forecast

Issued: Jan 3rd, 2021 4:00PM

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

Avalanche Canada JSmith, Avalanche Canada

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Recently formed storm slabs will be most reactive in wind affected areas at treeline and above. Be especially cautious as you transition into wind affected terrain.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

  

SUNDAY NIGHT: Cloudy with flurries; 3-5 cm. / Moderate, south ridgetop wind / alpine low temperature -11 / Freezing level valley bottom.

MONDAY: Snow; 5-10 cm, with another 5-10 cm overnight. / Strong, south ridgetop wind / alpine high temperature -6 / Freezing level valley bottom.

TUESDAY: Cloudy with isolated flurries; 0-3 cm. / Strong, southwest ridgetop wind / alpine high temperature -5 / Freezing level 900 m.

WEDNESDAY: Snow; 5-10 cm. / Strong, southwest ridgetop wind / alpine high temperature -4 / Freezing level 1300 m.

Avalanche Summary

On Sunday, numerous explosive triggered storm slab avalanches up to size 3.5 were reported just west of revelstoke.

On Saturday, a skier triggered a size 2 slab avalanche near the Gorge area. See the excellent MIN report Here.

Recently formed storm slab will be most reactive in wind affected terrain at treeline and above.

Snowpack Summary

15-25 cm of new snow brings recent snow totals to around 50 cm. Strong southwesterly winds, and mild temps have formed widespread storm slabs at all elevations.

Two persistent weak layers buried in early/mid Dec. are now 110-160 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next. The first layer has been primarily reported as small surface hoar. The next layer has been reported as a thin freezing rain crust, surface hoar, or thick rain crust depending on elevation and location. As a result, diligent investigation of the snowpack is required to get a handle on local conditions.

Terrain and Travel

  • Avoid lee and cross-loaded slopes at and above treeline.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Uncertainty is best managed through conservative terrain choices at this time.

Problems

Storm Slabs

An icon showing Storm Slabs

New snow, strong winds and rising freezing levels have created widespread storm slabs ripe for human triggers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

Two persistent weak layers buried in early/mid Dec. are now 80 to 150 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next .

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Jan 4th, 2021 4:00PM

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