Avalanche Forecast

Issued: Jan 21st, 2016 8:43AM

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

pgoddard, Avalanche Canada

South Columbia.

A warm and windy storm is driving danger up on Friday.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

Friday brings another 10-20 cm snow, moderate to strong SW winds and freezing levels around 1500 m. A few more cm are expected on Saturday, before a change to light winds, cool temperatures, cloudy skies and a few flurries by Sunday. 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. Forecast rain at low elevations on Friday may lead to wet loose/ wet slab activity, while higher up the mountain, continued storm slab and persistent slab activity is likely.

Snowpack Summary

New snow, rising temperatures and strong winds are likely to create storm slabs in many places and wind slabs on features lee to the south. This will also add load and stress to the already volatile persistent slab. This 30-60 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

Persistent Slabs

Numerous large persistent slabs have been triggered over the last few days. New storm loading will only accentuate this problem.

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

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. At low elevations, rain on snow may lead to loose wet/ wet slab avalanche activity that could run surprisingly far.

Choose well supported terrain without convexities.>Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid lee and cross-loaded terrain near ridge crests.>Avoid travelling at rain-soaked elevations, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Jan 22nd, 2016 2:00PM