Avalanche Forecast

Issued: Mar 18th, 2015 10:05AM

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

swerner, Avalanche Canada

Cariboos.

Human triggered avalanches continue to fail on a buried weakness 40-60 cm down. Avalanche danger may be higher if you see more then 20 cm of new snow. Keep it simple, use a conservative approach to terrain.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

A well-organized pacific frontal system will likely arrive onshore tonight. Interior regions will start to see effects of this system by Thursday with cloudy skies and light precipitation 5-10 mm. Ridgetop winds will blow strong from the West and freezing levels will hover between 1600-1800 m. Friday and Saturday will bring continued precipitation with accumulations up to 20 mm. Ridgetop winds will be moderate from the SW and freezing levels 1800-2000 m. On Sunday a ridge builds over the Interior keeping things dry and clear, yet again....

Avalanche Summary

On Tuesday, reports from the region indicated numerous natural slab avalanches up to size 2.5, and a skier remote (15 m away) slab avalanche size 2, failing on the mid-February facet/ crust interface which remains alive and well.

Snowpack Summary

At higher elevations, new snow up to 60 cm sits over a plethora of surfaces including moist snow, crusts, wind affected surfaces, and/or old wind slabs which may still be reactive to rider triggers. Previous strong winds have redistributed new snow into wind slabs on leeward terrain features. Lower elevations up to treeline are sporting spring-like, melt-freeze conditions. The recent storm snow is sitting over a weak facet/crust layer that was buried in mid-February and has been quite reactive recently. The late-January crust/surface hoar layer (over 1m deep) and the mid-January surface hoar (around 1.5m deep) have been dormant for several weeks.

Problems

Wind Slabs

Thick, touchy wind slabs sit over a weakness from mid-February and is reactive to natural and to human-triggered avalanches.

Avoid freshly wind loaded features.>Avoid cross loaded slopes at or above treeline.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

A persistent weak interface buried mid- February 30-60 cm below the surface is responsible for numerous large slab avalanches. Remote triggering from a distance is possible, and conservative terrain selection is recommended.

Remote triggering is a concern anywhere from 100-500 m away, watch out for adjacent slopes.>Be aware of the potential for wide propagations.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Mar 19th, 2015 2:00PM