Avalanche Forecast

Issued: Feb 21st, 2014 8:44AM

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

swerner, Avalanche Canada

Kootenay Boundary.

The snowpack is touchy and primed for human-triggered avalanches.Don't let the improving weather lure you into high risk scenarios.

Summary

Confidence

Fair - Timing of incoming weather systems is uncertain

Weather Forecast

High pressure building in the North will be responsible for a cooler and dryer NW flow. Some unstable disturbances are embedded in this flow, bringing scattered cloud and light precipitation. Models disagree with timing and precipitation amounts on Sunday.Saturday: Cloudy with sunny periods. Alpine temperatures near -12.0. Light northerly ridgetop winds.Sunday: Cloudy with some light snow up to 5 cm. Alpine temperatures near -16.0. Ridgetop winds light from the SW.Monday: Sunny. Alpine temperatures near -11.0. Ridgetop winds blowing light from the north.

Avalanche Summary

Natural slab avalanche activity up to size 2.5 on all aspects and elevations. Remote triggering and long fracture propagations continue and a skier remote size 3 (50 m away) was reported. Endless settlements and whumphing experienced while traveling on low angle terrain. Low elevation cut-blocks are releasing naturally at the persistent weak interface.

Snowpack Summary

Moderate to strong SW winds has loaded leeward and cross-loaded exposed slopes. There is over a metre of recent storm snow that is sitting on a weak layer that is a mixture of facets, surface hoar, melt-freeze crusts and any combination of these. The weak layer is widespread at all elevations and aspects and continued whumpfing and avalanche activity is reported. The storm slab continues to settle and become more cohesive allowing for longer fracture propagations and remote triggering. This persistent weak layer is expected to be a concern for some time; at least through the weekend.

Problems

Storm Slabs

Storm slabs are expected to continue to release naturally at higher elevations and especially where the wind has transported snow and built fresh, new wind slabs.

Remote triggering is a concern, watch out for adjacent slopes.>Use conservative route selection, stick to moderate angled terrain with low consequence and avoid overhead hazards.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Persistent Slabs

Expect the deeply buried weak layer to continue to produce very large and destructive avalanches. Slopes are primed for remote triggering and remains a concern on all aspects and elevations.

Avoid areas with overhead hazard.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid runouts where triggering slopes from below is possible.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

3 - 6

Valid until: Feb 22nd, 2014 2:00PM