Avalanche Forecast

Issued: Jan 31st, 2017 4:22PM

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

jlammers, Avalanche Canada

South Rockies.

The best and safest riding may be in sheltered terrain around treeline.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Wednesday: Overcast skies with possible sunny breaks / Moderate northeast winds / Alpine temperatures of about -19Thursday: Clear skies / Light ridgetop winds / Alpine temperatures of about -19Friday: Clear skies / Light ridgetop winds / Alpine temperatures of about -8

Avalanche Summary

No new avalanches have been reported. The main concern continues to be the possibility of triggering the weak faceted layers deeper in the snowpack. Ongoing moderate to strong wind at upper elevations has created thin fresh wind slabs reactive to human triggering .

Snowpack Summary

Up to 10 cm of recent low density snow has been redistributed over previous hard, wind-affected surfaces forming additional thin layers of wind slab in lee terrain at higher elevations. Below 1500 metres you may find an isolated thin breakable rain crust about 1 cm thick. The snowpack is quite variable throughout the region. In deeper snowpack areas, the snowpack appears to be well settled with isolated concerns about the mid-December facet layer buried 50-100 cm deep. In shallow snowpack areas and lower elevations, the snowpack is weak and faceted. For instance, in the Elk Valley north area near Crown Mountain last week the height of snow was 90 cm with foot penetration of 80 cm; or almost to ground. In these areas, the wind has formed isolated hard slabs above weak facets and created the potential for large persistent slab avalanches.

Problems

Wind Slabs

Wind slabs may still be reactive to the weight of a person. I'd approach any steep, wind-affected slope with caution.

Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

Triggering deeper weak layers remains possible where hard slabs sit above weak sugary snow. This is most likely in thin snowpack parts of the region.

Danger exists where denser snow overlies weak, sugary snow below.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Feb 1st, 2017 2:00PM