Avalanche Forecast

Issued: Jan 22nd, 2016 7:55AM

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

pgoddard, Avalanche Canada

South Columbia.

A Special Public Avalanche Warning is in effect for this region.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

A last pulse of 5-10 cm snow with easing SW winds and a 1000 m freezing level is expected on Saturday ahead of a cooling and drying trend starting Sunday morning. Cloudy skies, light winds, cool temperatures and a few flurries may give way to sunny skies on Sunday/Monday. For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

Numerous size 1-2 slabs were triggered naturally and by skiers over the last few days. Many of these failed at and below treeline, on buried surface hoar, about 20-40 cm deep. Many of these were triggered remotely, highlighting the volatility of the persistent slab. An increasing number of wind slabs have also been failing at alpine/ treeline elevations, and also running on surface hoar. It is likely that a natural avalanche cycle occurred on Friday in response to the warm, windy storm.

Snowpack Summary

The recent storm has created storm slabs in many places and wind slabs on features lee to the south. This has also added load and stress to the already volatile persistent slab. This 40-90 cm persistent slab overlies a variety of surfaces including large surface hoar, sun crusts, and facets. The persistent slab is ripe for human and natural triggers and is especially touchy at and below treeline. The mid and lower snowpack are generally well settled and strong.

Problems

Storm Slabs

The recent storm has created storm slabs in many areas, and wind slabs on slopes lee to the south. These could be easy to trigger with the weight of a person or sled.

Avoid lee and cross-loaded terrain near ridge crests.>Choose well supported terrain without convexities.>Use ridges or ribs to avoid wind loaded slopes.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Numerous persistent slabs have been triggered this week. Even as the weather improves, this problem could remain touchy.

Avoid steep open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Use conservative route selection and be aware of the possibility of remote triggering.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Jan 23rd, 2016 2:00PM