Avalanche Forecast

Issued: Mar 8th, 2020 4:18PM

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

Parks Canada snow safety, Parks Canada

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Great skiing conditions with the recent snow! Watch for storm slab development in steep terrain as the new snow settles, especially in areas with a buried sun crust. Minimize exposure to cornices where possible and avoid steep thin areas.

Summary

Weather Forecast

A high pressure system will dominate the landscape on Monday with mainly sunny skies for all areas. Alpine winds will be out of the the west at 40-60 km/h. Alpine temperatures stay in the -12 to -15'C range while valley bottoms will warm to near freezing during the afternoon. Winds and temperatures will increase on Tuesday.

Snowpack Summary

5-20 cm of snow Saturday night with light winds. Buried wind slabs are present in alpine lee areas. New sun crusts exist on steep solar aspects. 40-50 cm of recent snow sits over the Feb 29 crust interface on steep solar aspects. In thin snow pack areas a dense mid-pack sits over a weak, faceted base, while thick areas have a stronger base.

Avalanche Summary

Avalanche control on Sunday produced limited results with a few avalanches up to size 2.5 and several areas with no results. Cornice control resulted in small storm slabs on the slopes below. Several small natural storm slabs observed in steep terrain. Two skiers triggered a reloaded deep persistent size 1.5 in Lippalian 3 at Lake Louise.

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Problems

Storm Slabs

An icon showing Storm Slabs

Use caution when entering steep terrain. Soft new storm slabs are forming, and buried wind slabs are present in lee areas. In steep solar terrain these are sitting on buried sun crusts. Cornice exposure should also be minimized due to recent growth.

  • Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.
  • If triggered the wind slabs may step down to deeper layers resulting in larger avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Recent snow has increased the load on the basal facets and we continue to see occasional results on this layer. Avalanches are most likely in areas with a thin snowpack (<130cm) where the basal facets and depth hoar are the weakest.

  • Be aware of thin areas that may propogate to deeper instabilites.
  • Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3.5

Valid until: Mar 9th, 2020 4:00PM

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