Avalanche Forecast

Issued: Jan 1st, 2015 8:28AM

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

Avalanche Canada swerner, Avalanche Canada

A Special Public Avalanche Warning is in effect for the weekend. Stay cautious and be conservative in your terrain selection.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Increasing cloud, moderate west winds and some light flurries are expected overnight Thursday. On Friday, cloudy skies with light snow amounts near 5 cm. Alpine temperatures near -10. A brief lull in the pattern for Saturday as a second Pacific low deepens off the coast. This low could bring moderate amounts of snow Sunday afternoon and overnight into Monday, however; confidence is poor with timing and precipitation amounts due to model discrepancies.

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

Snow surfaces are variable with northerly, wind exposed aspects showing firm wind press or scoured exposed crust, and more sheltered locations have up to 30 cm of light, low density, faceted snow. In the alpine and at treeline, strong northerly winds have transported this snow into stiff and reactive wind slabs on opposite slopes. Up to 70 cm below the surface (more in wind affected areas) you will likely find a hard, thick crust which formed mid-December. At higher elevations this crust has facets (sugary) snow above it and well-preserved surface hoar up to 10 mm in size in sheltered locations at treeline and below. Where the crust exists, it may be bridging triggers from penetrating to deeper persistent weaknesses. However, on high alpine slopes above where the rain crust formed, or in areas where rain didn't occur, deeply buried facets may still be susceptible to triggering, especially in thinner snowpack areas.

Problems

Wind Slabs

An icon showing Wind Slabs
Between 15 and 30 cm of low-density snow has been transported by strong swirling winds into hard wind slabs. Initially winds blew from the NW and have now switched to the ESE, which means wind slabs are likely found in unsuspecting places.
Use ridges or ribs to avoid pockets of wind loaded snow.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
A crust that formed in mid-December is buried near 70 cm down. Not much is known about its distribution. Dig down and test weak layers and watch for this condition as you transition from below treeline to treeline and above.
Make observations and assess conditions continually as you travel.>Stick to well supported terrain and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 2nd, 2015 2:00PM

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