Avalanche Forecast

Issued: Jan 9th, 2015 7:40AM

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

Avalanche Canada Peter, Avalanche Canada

Continue making conservative terrain choices this weekend and be wary of any slope that did not slide during the last storm.

Summary

Confidence

Fair

Weather Forecast

Synopsis: The ridge of high pressure gives way to weak upper trough on Saturday bringing more cloud and unsettled conditions through Sunday. We could see flurries on the weekend but no significant accumulation. Ridge winds are generally light or moderate from the W-NW. The ridge should rebuild on Monday bringing drier conditions and more sunshine. The freezing level remains at valley bottom throughout the period.

Avalanche Summary

Further evidence of the widespread and large natural avalanche cycle was reported on Thursday. Avalanches up to size 3 were reported from all aspects at all elevations. Conditions remained touchy to skier triggered on Thursday, particularly around Rossland. There is an interesting report from Mount Kirkup (west of Rossland) where an experienced observer describes this as one of the most active avalanche periods they have seen in the region. They remotely triggered one slab from 20 degree terrain and observed other naturals occurring on relatively low angle slopes.

Snowpack Summary

The current snow surface consists of a melt-freeze crust with surface hoar on top in sheltered areas. This crust is reported on aspects to ridge top in some areas and below 1800 m in others. Fresh wind slabs are likely in exposed alpine and treeline terrain. The main snowpack concern is a buried surface hoar layer (down 80-100 cm), which is sitting on a rain crust in some places. This widespread persistent weakness exists at all elevation bands and remains a concern for triggering. At the base of the snowpack, a crust/facet combo appears to have gone dormant for the time being.

Problems

Persistent Slabs

An icon showing Persistent Slabs
A buried persistent weak layer (down 80-100 cm) has been responsible for numerous large natural and rider triggered avalanches this week. Triggering remains a concern with the potential for creating large high-consequence slides.
Choose conservative lines and watch for clues of instability.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Storm Slabs

An icon showing Storm Slabs
Warm temperatures followed by cooling this weekend could help stabilize this problem, particularly if there is no surface crust. Also, watch for thin wind slabs to develop in exposed lee terrain.
Use careful route-finding and stick to moderate slope angles with low consequences>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Jan 10th, 2015 2:00PM