Parks Canada marcus waring, Parks Canada

Waterton Lakes National Park Avalanche Forecast

Dec 31st, 2019 4:00PM

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

Westerly winds have rapidly increased the severity of our Windslab problem.  Avoid wind loaded slopes be mindful of your overhead hazard.

Summary

Weather Forecast

Tuesday Night- Expecting 2-5 mm of precip by Wed AM With continued strong to extreme West wind.

Wednesday- A mix of sun and cloud with Strong - Moderate wind. Isolated flurries. Freezing Level 1500m

Thursday- A mix of Sun and cloud with a chance of flurries.

Snowpack Summary

Strong - Extreme Westerly winds continue to develop Windslab in lee areas. A deteriorating melt freeze crust exists on all aspects up to 1800m. Above 1800m, 85-120cm of well settled snow from previous storm sits on top of a weak facet/ melt freeze crust near the base of the snowpack. Reactivity of this basal weakness is variable & warrants caution.

Avalanche Summary

No new observations

Confidence

Wind effect is extremely variable

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely - Possible

Expected Size

1 - 2

Fresh Windslabs reactive to ski cuts at ridge top today at cameron lakes. Warming temperatures wednesday will make Windslabs easier to trigger

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Use caution in lee areas. Recent wind loading has created fresh slabs.

Aspects:

North, North East, East, South East, South, North West.

Elevations:

Alpine, Treeline.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Possible - Unlikely

Expected Size

2 - 3

The November facet/ melt freeze crust combo still lurks near the base of the snowpack. This layer could still be triggered by people in thinner snowpack areas, or by large triggers including cornices or smaller avalanches.

  • Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
  • Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Valid until: Jan 3rd, 2020 4:00PM