Avalanche Forecast

Issued: Apr 23rd, 2021 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Cornices and Loose Wet.

Avalanche Canada JSmith, Avalanche Canada

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Final forecast for the season! Strong solar radiation increases the likelihood of cornice failures and wet loose avalanches. Back off slopes as the surface becomes moist or wet with daytime warming and avoid slopes with large cornices overhead. 

Summary

Confidence

High -

Weather Forecast

  

FRIDAY NIGHT: Clear / Light, northeast ridgetop wind / alpine low temperature -5 / Freezing level 1500 m.

SATURDAY: Sunny / Light, northeast ridgetop wind / alpine high temperature 5 / Freezing level 1600 m.

SUNDAY: Sunny / Light, northeast ridgetop wind / alpine high temperature 7 / Freezing level 1800 m.

MONDAY: Sunny / Moderate, west ridgetop wind / alpine high temperature 6 / Freezing level 1600 m.

Avalanche Summary

A few naturally triggered wet loose avalanches up to size 1.5 were reported in this region on Thursday.

NOTE: Observations are very limited during this time of year.

Snowpack Summary

The snowpack has been undergoing a melt-freeze cycle with successive days of warm sunny weather. Strong solar radiation and warming will likely initiate wet loose avalanches as the snow loses cohesion. As the heat penetrates deeper into the snowpack, operators have reported larger wet slab avalanches. These avalanches are dense, destructive, and can run far, reaching otherwise snow-free valley bottoms. Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight. Check out the Forecaster's Blog for information on how to manage these spring conditions. 

The snowpack is overall strong and settled in most areas, however, sustained warming can increase the likelihood of large avalanches failing on deeply buried weak layers. This is most likely to occur on steep, rocky alpine slopes with a shallow or thin to thick snowpack.

Glide cracks releasing as full depth glide slab avalanches become more common in the spring and are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.

Terrain and Travel

  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Avoid exposure to slopes that have cornices overhead.

Problems

Cornices

An icon showing Cornices

Strong solar radiation and warming can trigger large cornices that hang over ridge lines. Cornice falls are a hazard on their own, but could also trigger large avalanches on the slopes below.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Loose Wet

An icon showing Loose Wet

 Wet loose avalanches become increasingly likely during the heat of the day.  

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 26th, 2021 4:00PM