Avalanche Forecast

Issued: Feb 13th, 2020 5:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Although avalanche conditions are improving there is still potential to trigger avalanches on wind loaded slopes and large steep terrain features.

Summary

Confidence

High - Confidence is due to a stable weather pattern; little change is expected for several days.

Weather Forecast

THURSDAY NIGHT: Light flurries with 5-10 cm of low density snow, moderate wind from the west, alpine temperatures drop to -10 C.

FRIDAY: Mainly cloudy with isolated flurries and up to 5 cm of snow, moderate wind from the west, alpine high temperatures around -6 C.

SATURDAY: Mainly cloudy with sunny breaks and isolated flurries, light wind from the southwest, alpine high temperatures around -6 C.

SUNDAY: 5-10 cm of snow overnight then clearing in the afternoon, light wind from the west, alpine high temperatures around -6 C.

Avalanche Summary

A few small (size 1) wind slabs have been human triggered at treeline and alpine elevations over the past few days.

On Monday there were reports from the central part of the region of two explosives triggered deep persistent avalanches size 2.5 and 3 running on north aspects in the alpine. One of these ran on facets sitting glacial ice.  

Snowpack Summary

20-50 cm of low density snow has fallen over the past week. This snow has shown some reactivity at higher elevations where it has been redistributed it into isolated wind slabs. This snow sits above a rain crust that extends up to 1800-2000 m. The middle of the snowpack is generally settled but the base of the snowpack contains basal facets. It remains possible to trigger these deep weak layers in shallow rocky start zones or from a heavy trigger such as a cornice fall. 

Terrain and Travel

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Conditions may have improved, but be mindful that deep instabilities are still present.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent light snowfall combined with elevated and shifting winds have built wind slabs on a variety of aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A layer of weak, sugary facets persists at the bottom of the snowpack at higher elevations. Steep, rocky alpine features where the snowpack transitions from thick to thin are the likely trigger points for this deep persistent slab problem.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Feb 14th, 2020 5:00PM

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