Avalanche Forecast

Issued: Feb 17th, 2020 4:00PM

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

Parks Canada deryl kelly, Parks Canada

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Jasper.

Human triggering is possible in areas where windslab is present. This WILL trigger the deep instability, especially in areas where there is significant spacial variability and wind effect.

Summary

Weather Forecast

Fair weather approaches! A surface ridge, from the north and will push isolated flurries through the northern front ranges Monday; finally clearing over the day Tuesday. Broken sun and an alpine high temperature of -12 C. Wind, NW 10 km/h gusting to 30 km/h.

Find the Alberta Rockies weather synopsis here: Mountain Weather Forecast

Snowpack Summary

Variable strength windslab on the surface. Pronounced cornice development on northerly aspects and cross loaded features treeline and above. The mid-pack is bridging the deeper basal facets and depth hoar in some locations.

Average HS at treeline: ~180cm.

Avalanche Summary

"The Beast has awakened!" Experienced back-country users remotely triggered a very large avalanche (sz 4) on Whistlers Peak yesterday. The pair observed significant wind effect in the area and unknowingly triggered the windslab from 100m away, which then initiated the entire season's snowpack on the deep persistent layer. Further details here: MIN

Confidence

Intensity of incoming weather systems is uncertain on Wednesday

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs are widespread through the region with new and previous loading in lee features. Sensitivity will vary with local loading and wind patterns.

  • Assess start zones carefully and use safe travel techniques.
  • Watch for pockets of hard windslab in steep alpine terrain features..

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Shallow snowpack areas, windslabs and/or large triggers such as cornice failures could trigger this deep layer. The consequences of triggering will likely be severe!

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3.5

Valid until: Feb 18th, 2020 4:00PM

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