Avalanche Forecast

Issued: Jan 3rd, 2021 4:00PM

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

Avalanche Canada JSmith, Avalanche Canada

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Strong southwesterly winds continue to form fresh wind slabs reactive to human triggers on lee features at treeline and above. Wind slabs in motion may step-down to deeper weak layers, resulting in large avalanches.

Summary

Confidence

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

Weather Forecast

  

SUNDAY NIGHT: Cloudy with isolated flurries; 0-3 cm. / Strong, south ridgetop wind / alpine low temperature -12 / Freezing level valley bottom.

MONDAY: Cloudy with flurries; 3-5 cm. / Strong, south ridgetop wind / alpine high temperature -6 / Freezing level valley bottom.

TUESDAY: Cloudy with isolated flurries; 0-3 cm. / Strong, south ridgetop wind / alpine high temperature -5 / Freezing level 1000 m.

WEDNESDAY: Snow; 5-10 cm. / Strong, southwest ridgetop wind / alpine high temperature -4 / Freezing level 1400 m.

Avalanche Summary

New snow and wind may continue to overload a weak layer of surface hoar that has been observed in the areas surrounding Valemount. Large human triggered avalanches are likely.

Data in this region is sparse. Please submit your observations to the Mountain Information Network. 

Snowpack Summary

Another layer of large surface hoar was reported in the areas surrounding Valemount and has now been buried by 15-20 cm. of recent snow. 

An active weak layer is now down 40 to 80 cm. The distribution of this layer is variable. In some areas it's surface hoar and/or a crust; in others this layer may be difficult to find if it exists at all. Recent human triggered avalanches have been reported on this layer and have been most numerous in the areas surrounding Valemount.

There is a prominent crust near the base of the snowpack. This crust likely has weak facets above and/or below it. There have been no recent avalanches reported on this layer, but would be most likely to trigger in steep, shallow, rocky terrain, with a thin to thick snowpack.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be careful as you transition into wind affected terrain.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

Problems

Wind Slabs

An icon showing Wind Slabs

Strong southwesterly winds continue to form fresh wind slabs reactive to human triggers on lee features at treeline and above. Wind slabs in motion may step-down to deeper weak layers, resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

Concern remains for a very weak layer of surface hoar down 50-70 cm. This layer has been found to be most prevalent at treeline and below in the areas surrounding Valemount.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

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