Avalanche Forecast

Issued: Jan 26th, 2013 9:39AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Sunday: Northwest flows aloft will bring some snowfall accumulations. Snow amounts 5-10 cm accompanied by moderate ridgetop winds from the West. Alpine temperatures near -6.0 and freezing levels at 800 m. Monday: A low pressure system over Gulf of Alaska will move onto the north coast, sliding South bringing light precipitation. Snow amounts near 5cm with moderate NW ridgetop winds. Alpine temperatures near -6 and freezing levels hovering around 800 m. Tuesday: Light-Moderate snowfall amounts expected. Alpine temperatures near -3.0. Ridgetop winds will shift out of the West  in the light ranges.

Avalanche Summary

On Friday, reports of size 1-2 natural slab avalanches occurred. Explosive avalanche control produced numerous size 1-2 slab avalanches on NW-NE aspects from 1800-2200 m. Most releases were within the old storm snow.

Snowpack Summary

New snow accumulations around 25 cm overlie a variety of old surfaces including hard wind slabs, thin and thick crusts and large surface hoar crystals which can be found in sheltered areas below treeline. Recent winds have shifted snow into soft and hard slabs anywhere from 25-40 cm thick on lee slopes. The early January surface hoar layer is buried down 40-80 cm and seems to be gaining strength. Reports indicate that this layer is mainly unreactive, and would require a large trigger to set it off. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in unsupported, shallow, rocky terrain where more faceting has taken place.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs have built, and in areas affected by wind, wind slabs up to 40 cm thick are likely encountered. These continue to be touchy to rider triggers. In other areas be alert for loose dry avalanches out of steeper terrain.
Be cautious of sluffing in steep terrain; especially in areas where terrain traps lurk below.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Jan 27th, 2013 2:00PM