Avalanche Forecast

Issued: Jan 7th, 2018 4:28PM

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

pgoddard, Avalanche Canada

South Rockies.

Conditions are variable across the region. Back off if you encounter warning signs like whumpfing or cracking.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY: Strong to gale south-west winds. Flurries. Alpine temperature near -5.TUESDAY: Strong south-west winds dying out. Around 5 cm snow. Alpine temperature near -2. A further 5-10 cm snow overnight.WEDNESDAY: Strong south-west winds. Light snow. Alpine temperature near -10.

Avalanche Summary

No new avalanches have been reported in the last couple of days, but some whumpfing was felt on Saturday. Earlier in the week, persistent slabs were failing easily with natural and human triggers. With warming or increased load by snow and/or wind-loading, persistent slab activity may increase again.

Snowpack Summary

Wind slabs may exist lower on the slope than normal, due to recent extreme south-west winds. Windward alpine slopes are scoured; and variable wind slabs are found at treeline and alpine elevations. A weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found at treeline and below. Avalanches on this layer may be triggered by the weight of a person in certain locations. As temperatures warm, the slab above this weakness may become easy to trigger.Deeper in the snowpack, an early season rain crust and sugary facets make up the picture. Overall snowpack depths are variable across the region. It's generally shallower in the east.

Problems

Wind Slabs

Wind slabs can be found at treeline and alpine elevations. Recent extreme winds have stripped some aspects and may have left wind slabs further down slope than normal.

Back off if you encounter whumpfing, hollow sounds or shooting cracks.The best and safest riding will be on slopes that have soft snow without any slab properties.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Weak layers are buried within a prime depth range for human triggering. These are most prevalent at and below treeline.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Avoid convex slopes around treeline.Choose slopes that are well supported and have limited consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 8th, 2018 2:00PM