Avalanche Forecast

Issued: Feb 25th, 2016 8:32AM

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.

pgoddard, Avalanche Canada

Northwest Inland.

Avalanche danger may be higher in the north of the region, where a buried weak layer has been recently reactive.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

The first of two cold fronts is expected to bring 5-10 cm snow on Friday, with strong south-westerly winds and the freezing level rising to around 1300 m. There is a lull on Saturday before the second front brings light snow and strong winds again on Sunday.

Avalanche Summary

Isolated wind slab avalanches were reported over the last couple of days. In the north of the region, a small natural avalanche that stepped down to the early January surface hoar on Sunday is a good reminder that this layer needs to remain a concern. Deeply buried persistent weak layers in the alpine also woke up in the north of the region over the weekend when several large avalanches released on basal facets. This weak layer was reported to be reactive to skier triggering from thin spots, as well as heavy triggers such as a smaller avalanches or cornice failures.

Snowpack Summary

Recent strong winds have created wind slabs on a variety of slopes at alpine and treeline elevations. Incoming snow will bury wind slabs, a thin sun crust on sunny aspects and surface hoar in isolated sheltered and shady locations. 40-80 cm of snow sits above a melt freeze crust buried around February 12th. This crust extends up to about 2000 m. Below this, a layer of surface hoar buried late in January remains a lingering concern. Shallow snowpack areas may also have a weak base of facets near the ground.

Problems

Wind Slabs

Recently formed wind slabs are lurking on many alpine and treeline slopes. Incoming snow, wind and rising temperatures may create a new storm slab problem above older wind slabs.

Travel on ridges and ribs to avoid wind loaded areas. >Be aware of the potential for wide propagations due to the presence of hard windslabs.>Be alert to conditions that change with elevation. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A storm slab or wind slab could step down and trigger a deeply buried weak layer, creating a surprisingly large avalanche.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.>Be aware of the potential for large, widely propagating avalanches due to the presence of buried weak layers.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Feb 26th, 2016 2:00PM