Avalanche Forecast

Issued: Nov 27th, 2019 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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The most likely place to trigger avalanches is where the wind has formed new slabs at higher elevations.

Summary

Confidence

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.

Weather Forecast

WEDNESDAY NIGHT: Clear, 40 km/h wind from the northeast, alpine temperatures drop to -12 C.

THURSDAY: Sunny, 20 km/h wind from the northeast, alpine high temperatures around -8 C.

FRIDAY: Sunny, light wind from the northeast, alpine high temperatures around -3 C.

SATURDAY: Sunny, light wind from the northeast, alpine high temperatures around -5 C.

Avalanche Summary

Last weekend's storm likely caused a widespread cycle of natural avalanches, but there have been few reports since then. Looking forward, avalanches may still be possible to trigger in any areas where the recent snow has buried a smooth surface and where wind has formed new slabs. Concern is reduced in areas where the snow depths have not yet reach the threshold for avalanches.

Snowpack Summary

Strong wind from the northeast has likely formed new wind slabs on west and south facing slopes at higher elevations. Last weekend's storm delivered much more snow in western parts of the region (e.g. 150 mm of precipitation at Shames and only 36 mm at Rosswood). Recent observations from Shames suggest this resulted in about 30 cm of snow at 750 m, 100 cm of snow at 1200 m, and likely over a metre of snow in the alpine (see this MIN report). While the storm snow has likely settled since then, there is still some uncertainty about how well it has bonded to crust that it buried.

Problems

Wind Slabs

An icon showing Wind Slabs

You may find old hard slabs on all aspects and softer fresh slabs on west and south facing slopes. Picking out where the new snow sits on a smooth surface and where it is anchored in place by rocks may still be tricky.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 28th, 2019 4:00PM

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