Avalanche Forecast

Issued: Dec 22nd, 2018 4:23PM

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

kdevine, Avalanche Canada

South Rockies.

The snowpack in the South Rockies remains generally weak. The snow that fell over the past week sits on a persistent weak layer that will need more time to adjust to the new load. Conservative terrain selection is recommended.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SATURDAY NIGHT - Mainly cloudy with clear periods and isolated flurries / southwest winds, 15-30 km/h, gusting to 50 km/h / alpine low temperature near -11SUNDAY - Cloudy with sunny periods and isolated flurries / southwest winds, 20-40 km/h / alpine high temperature near -7MONDAY - Cloudy with sunny periods and isolated flurries / light west winds / alpine high temperature near -7, low temperature near -10TUESDAY - Cloudy with sunny periods / light southwest winds / alpine high temperature near -9, low temperature near -11

Avalanche Summary

No new avalanches were reported in the region on Saturday.One natural size 2 avalanche that was triggered by a cornice was reported in the region on Friday. One size 1.5 explosives triggered avalanche was reported on Thursday.

Snowpack Summary

60-90 cm of recent snow has formed a slab that sits on a weak layer of facets (sugary snow) that formed during the dry weather in early December. Avalanche activity on this layer has slowed down to some degree, but in certain terrain features, it may still be easy for humans to trigger avalanches on this layer. Steep features where the underlying ground cover is smooth, places where the snowpack transitions from deep to shallow, and large convex features are some of the most likely places to trigger this layer.The lower snowpack has a weak structure composed primarily of facets. It is likely that an avalanche triggered on the persistent slab would step down to the lower facets, resulting in a full depth avalanche.

Problems

Persistent Slabs

60-90 cm of snow sits on a weak layer of facets (sugary snow). The snow below this layer consists primarily of facets all the way to the ground. Avalanches triggered on this layer will likely step down to the ground, resulting in large avalanches.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Be suspect of thin snowpack areas, where it may be easier to trigger the persistent slab.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Dec 23rd, 2018 2:00PM