Avalanche Forecast

Issued: Mar 10th, 2013 9:33AM

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.

triley, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Monday

Weather Forecast

Overnight and Monday: A weak disturbance is moving Southwards across the Interior Ranges bringing light precipitation and strong Northerly winds. Freezing levels should drop to valley bottoms overnight and then rise to about 1500 metres.Tuesday: A Low pressure system is expected to track inland from the South Coast during the day bringing moderate to heavy precipitation and freezing levels rising up to about 2000 metres. Winds becoming strong Westerly.Wednesday: Another frontal system is expected to move inland from the coast.

Avalanche Summary

One skier accidental size 2.0 avalanche was reported from the Selkirks in the South of the region near the Kootenay Boundary region border; see incident report database for more info. Loose moist snow and natural cornice falls resulted in numerous avalanches in the Selkirks and Monashees during the period of strong solar radiation on Saturday. No avalanches were reported to have released on the February 12th weak layer.

Snowpack Summary

New wind slabs are developing above a new surface hoar layer on shaded aspects and a sun crust on solar aspects. The weak layer of surface hoar that was buried on February 12th is now down about 100-150 cm and was not triggered by cornice falls over the weekend. Some areas report that the February 12th surface hoar is rounding and getting harder to shear in snow profile tests, but continues to give planar shears when it does fail. Avalanches failing on the February 12th layer have become a low probability/ high consequence situation.

Problems

Wind Slabs

Thin new wind slabs may form in exposed lee terrain over the next couple days. Older wind slabs may still be triggered in isolated areas like steep unsupported terrain.

Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A weak layer of buried surface hoar down about 100-150 cm may be triggered by large loads like re-grouping, cornice fall, or smaller avalanches in motion.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Mar 11th, 2013 2:00PM