Avalanche Forecast

Issued: Feb 3rd, 2014 9:08AM

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

Avalanche Canada ghelgeson, Avalanche Canada

I've bumped up the hazard in response to increased winds Monday afternoon. Be advised that wind slabs may have more "bite" on Tuesday than you've seen recently.

Summary

Confidence

Fair - Wind effect is extremely variable

Weather Forecast

Synopsis: A very strong ridge of high pressure continues to dominate the weather pattern. The optimist sees a storm in the models next weekend. The realist says its still too early to count on.Tuesday: Sky: Overcast; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, NEWednesday: Sky: Clearing; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, NE, Mod NE at ridgetop.Thursday: Sky: Clear; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, N

Avalanche Summary

Fast moving loose dry avalanches and small wind slabs continued to be sensitive to human triggering Sunday.Deep Persistent Slabs have been removed from the problem portion of the forecast because it's probably a 1:1000 slope event at this time, but they haven't totally gone away. Two large natural avalanches (size3) were observed on a steep south facing alpine feature south of Revelstoke on Saturday.

Snowpack Summary

Snow totals from the last pulse on Wednesday (140129) range from 5 - 20 cm with the greatest accumulations in the south of the region. This snow is faceting quickly in the cold temps. In wind exposed terrain, especially in the alpine, winds continue to form shallow wind slabs that vary wildly with regard to depth, hardness and distribution. These wind slabs should stick around a bit longer than we're normally accustomed to as they are resting on a weak layer that is composed of large grained surface hoar (widespread in most sheltered and shaded areas at all elevations), a sun crust on open south facing slopes, faceted grains (in colder areas or areas with a thinner snowpack), or a combination of any of the above.Most of the snowpack is generally well consolidated. However, in thinner snowpack areas a facet/crust weakness may exist near the bottom of the snowpack. The depth of this layer makes human triggering unlikely, but the consequences could be disastrous. In this low probability, high consequence scenario it's best practice to avoid thin or rocky areas on steep, convex, unsupported slopes.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent low density accumulations rest on a hard surface which is covered with slippery surface hoar on many slopes. This combination will keep both active sluffing and thin wind slab problems alive longer than we're normally accustomed to.
Carefully consider the impact a thin wind slab will have on your proposed line, especially in high consequence terrain. Have a backup line in mind in case you need to seek more sheltered riding. >On steep slopes, pull over periodically or cut into a new line to manage sluffing.>Watch for terrain traps where small amounts of snow will acumulate into deep deposits.>Highmark or enter your line well below ridge crest to avoid wind loaded pillows.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 4th, 2014 2:00PM

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