Avalanche Forecast

Issued: Dec 15th, 2019 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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There are two weak layers in the top 60 cm of the snowpack that could be reactive to human triggers, especially in wind affected and shallow snowpack areas. The deeper layer may be difficult to assess and predict, so conservative terrain selection is recommended.

Summary

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

SUNDAY NIGHT - Cloudy with clear periods / northwest wind, 20-30 km/h / alpine low temperature near -10

MONDAY - Mainly cloudy with isolated flurries / southwest wind, 20-40 km/h / alpine high temperature near -6

TUESDAY - Cloudy with sunny periods and isolated flurries / southwest wind, 20-40 km/h / alpine high temperature near -5

WEDNESDAY - Mainly cloudy with isolated flurries / southwest wind, 20-30 km/h / alpine high temperature near -5

Avalanche Summary

There were reports of a size 1 human triggered avalanche, and natural size 2 avalanche on Saturday that released on the persistent weak layer that is down about 50-60 cm

There were a few reports of explosives triggered storm slab avalanches up to size 2 on Friday.

There were a few human and explosives triggered storm slab avalanches size 1-2 reported on Thursday.

Check out this MIN report of an avalanche in the Big White backcountry on Thursday.

Snowpack Summary

15-30 cm of recent fresh snow sits on a weak layer of feathery surface hoar in many areas, and on a crust on steep south facing slopes. This layer may be reactive to human triggers, especially in wind affected areas.

There is also a persistent weak layer down approximately 50-60 cm that mainly consists of a crust with sugary faceted snow on top of it. This layer may be reactive to human triggers, especially in shallow, rocky areas.

Problems

Persistent Slabs

An icon showing Persistent Slabs

There are two prominent weak layers in the snowpack right now that are of concern. The first is a layer of surface hoar that was buried last week, and is approximately 20-30 cm deep. The second is a persistent weak layer that is now buried 50-60 cm. Both layers could potentially be reactive to human triggers. Be aware that if the shallower layer is triggered, it may step down to the deeper layer, resulting in a large avalanche.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 16th, 2019 5:00PM

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