Avalanche Forecast

Issued: Jan 20th, 2016 8:06AM

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

pgoddard, Avalanche Canada

South Columbia.

Touchy persistent slab + new snow + rising temps + strong winds = a good recipe for avalanches.

Summary

Confidence

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

Weather Forecast

A Pacific front embedded in a southerly flow brings snow (20-40 cm total), strong S to SW winds and freezing levels rising to around 1500 m on Thursday and Friday. Precipitation and winds ease and temperatures drop on Saturday.For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

Avalanche activity has been widespread over the last few days as recent snow has reached a critical load above a volatile weak layer. Human and naturally-triggered avalanches have been most prevalent below treeline, but have also occurred at higher elevations in some parts of the region. These have mostly been in the size 1-2 range, with many triggered remotely from a distance. Wind slabs have also been reported in wind-exposed terrain.

Snowpack Summary

A 40-80 cm persistent slab overlies a variety of surfaces including large surface hoar, sun crusts, and facets. This slab is ripe for human triggers and is especially touchy below treeline. Recently formed wind slabs also exist on lee features at alpine and treeline elevations. Incoming snow, with warming and strong winds, will increase the size and likelihood of the persistent slab problem, as well as adding new storm slab problems. The mid and lower snowpack are generally well settled and strong.

Problems

Persistent Slabs

A volatile persistent slab has been failing with light loads. These slabs will probably get bigger and more reactive with the incoming storm.

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

Likely - Very Likely

Expected Size

1 - 5

Storm Slabs

New snow, rising temps and strong southerly winds are expected to create a storm slab problem. Storm slabs/ wind slabs may pick up a surprising amount of mass.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 21st, 2016 2:00PM