Avalanche Forecast

Issued: Jan 6th, 2015 8:53AM

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

Hazard remains HIGH on Wednesday as the storm ends. Tricky conditions are expected to persist for the next few days.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

The storm conditions should end on Wednesday. Overnight Tuesday, the region is expected to see another 5-10mm of precipitation with moderate-to-strong SW alpine winds. On Wednesday, alpine winds wind remain moderate-to-strong but will switch from SW to NW. Light flurries are expected during the day and a temperature inversion is expected to form with a layer of warm air sitting at around 2000m. Similar conditions are expected on Thursday and Friday with a temperature inversion, light alpine winds, and generally dry conditions.

Avalanche Summary

A natural cycle was reported on Monday but observations were limited due to the storm. 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.  Natural storm and wind slab avalanches are expected to continue on Wednesday and the potential for human triggering remains very high.

Snowpack Summary

Recent winds have been highly variable with strong winds from almost all directions in the last few days.  The most recent strong winds have been from SE-SW. 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 30-70 cm of new snow. The new snow may be resting on older wind slabs or surface hoar in northern areas. In the mid-pack 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
Avoid freshly wind loaded features.>Travel in avalanche terrain is not advised without professional level safety systems and guidance.>

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.
Be aware of the potential for large, deep avalanches.>Use caution around convexities, ridge crests, rock outcroppings and anywhere else with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 6

Valid until: Jan 7th, 2015 2:00PM