Avalanche Forecast

Issued: Jan 5th, 2015 8:13AM

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

Avalanche Canada rbuhler, Avalanche Canada

Storm conditions will keep the hazard elevated in the south of the region for the next couple days. Stick to simple, mellow terrain and give the storm snow a few days to stabilize.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The next storm pulse hits the NW on Monday night. Southern parts of the inland region may see 10-20mm of precipitation whereas the north is around 5-10mm. Alpine wind is expected to be moderate-to-strong from the SW and treeline temperatures are expected to be around -12C. There will be a bit of a break during the day on Tuesday before the next storm pulse hits on Tuesday night. Another 5-10mm is expected. On Wednesday, a temperature inversion is expected to form and a layer of above-zero air may sit in the alpine. Light precipitation is possible and winds are expected to be moderate from the SW. Thursday looks to be the warmest with freezing levels reaching up to 2500m. The inversion should keep the valleys cooler. Dry conditions are expected on Thursday with light winds.

Avalanche Summary

Reports of unobserved natural activity occurring on Sunday in the south of the region.  Also reported was a size 1 skier triggered storm slab avalanche.  This released down 15-30cm on a convex roll at treeline.  Storm slabs are expected to continue to build in the south of the region.  Wind slab formation is expected across the region.

Snowpack Summary

Recent winds have been highly variable with strong W-NW winds followed immediately by strong SE-NE winds. Hard and soft wind slabs should be expected on a variety of slopes in open terrain. rain was reported to almost 2000 m on New Years Day in the southern part of the region. Since then there's been around 20-50 cm of new snow. The new snow may be resting on older wind slabs or surface hoar in northern areas. Down 40-70 cm you may find another surface hoar layer, although it appears to be spotty in distribution. Near the bottom of the snowpack is a crust facet combo that was buried in mid-November. This layer is currently dormant and produces variable results in snowpack tests. I suspect it will remain sensitive to new inputs in the form of new snow and wind for the foreseeable future.

Problems

Storm Slabs

An icon showing Storm Slabs
The new snowfall adds to the snow that fell on Saturday night.  In the deeper snowfall areas of the south of the region, this may be enough to form widespread storm slabs.  The primary concern across the region is wind slabs associated with the storm
Travel in avalanche terrain is not advised without professional level safety systems and guidance.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
New loading from snowfall and strong winds could 'wake up' deeper persistent weaknesses and produce isolated very large avalanches.
Use caution around convexities, ridge crests, rock outcroppings and anywhere else with a thin or variable snowpack.>Be aware of the potential for large, deep avalanches.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 6

Valid until: Jan 6th, 2015 2:00PM