Avalanche Forecast

Issued: Feb 20th, 2021 3:00PM

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

Avalanche Canada mkoppang, Avalanche Canada

Email

Strong winds are making the upper snowpack more reactive as windslabs develop in most open areas. A storm with strong winds is forecast to reach the region on Monday. 

Summary

Confidence

Moderate -

Weather Forecast

Sunday will see the warm front with the associated precipitation begin to move into the region. There will only be minor accumulation on Sunday before the main mass of the storm arrives on Monday with 15-20cm of snow. Winds are still going to be strong out of the SW so as the storm begins to arrive we can expect avalanche danger to increase. 

Avalanche Summary

No new natural avalanche activity was observed on Saturday but conditions felt primed for human triggered avalanches due to the presence of these new windslabs. 

Snowpack Summary

The effects of the recent winds are noticeable with windslabs in open terrain at treeline and above. These windslabs are 10-20cm thick in areas travelled on Saturday but we can expect them to increase in depth and reactivity as winds continue overnight. Any windslab that starts in the upper snowpack will likely step down to the Jan 29th persistent interface down 40-60cm. Watch for these problems along ridgelines, and in lee terrain mainly on N and E aspects. 

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Pay attention to isolated alpine features as well as cross-loaded features at treeline.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Watch for areas of hard wind slab on alpine features.

Problems

Wind Slabs

An icon showing Wind Slabs

Strong winds have created new slabs at treeline and alpine elevations. These will be sitting on loose facets and could be quite touchy.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

Windslabs in the upper snowpack may step down to the Jan 29th interface down 50-80cm. Dig down and evaluate this interface as you travel. 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Feb 21st, 2021 3:00PM