Avalanche Forecast

Issued: Dec 19th, 2014 8:23AM

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

triley, Avalanche Canada

Northwest Inland.

Avalanche danger is increasing as the storm slab continues to develop.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Very strong Southerly winds moving in from the coast. 3-5 cm by Saturday morning, 5-8 during the day on Saturday. Winds becoming moderate Southwest by Sunday morning with another 5-8 cm and then a few more cms during the day. Monday cooling and drying out with strong Westerly winds.

Avalanche Summary

There are no new avalanche reports from the region. The forecast new storm is expected to develop a new storm slab that may increase avalanche activity.

Snowpack Summary

The new storm is expected to develop a storm slab above the dusting of new snow which overlies weak surface hoar reported to exist up to at least treeline elevation. Below the new snow you'll likely find wind-scoured surfaces and old wind slabs in exposed terrain, and settled storm snow closer to treeline. Near the base of the snowpack, weaknesses such as the mid-November crust-facet layer are still of concern. I'd use extra caution around steep, unsupported high elevation terrain as avalanches at this interface could propagate over wide distances.

Problems

Storm Slabs

A new storm slab is developing above a mix of crusts, settled storm snow, and surface hoar. Loose dry snow may slide easily off of the old surface crust.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid wind loaded and cross loaded slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

The new storm load may overload the deeply buried weak layer combination of crust, facets, and surface hoar.

Be aware of thin areas that may propogate to deeper instabilites.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 20th, 2014 2:00PM