Avalanche Forecast

Issued: Jan 16th, 2015 8:28AM

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

Avalanche Canada jlammers, Avalanche Canada

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Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

A dry ridge of high pressure will develop on Saturday before another pacific frontal system makes its way inland bringing up to 15cm of snow for Sunday. On Monday, light snowfall is possible; however, a general clearing pattern is expected for early next week. Freezing levels are expected to sit at about 800m on Saturday, and then rise to about 1200m on Sunday and Monday. Winds should remain southwesterly throughout the period, increasing from light on Saturday to Strong on Sunday and Monday.

Avalanche Summary

At the time of publishing this bulletin, no new avalanche activity had been reported. That said, on Saturday I'm sure there was a round of fast sluffing in steep, sheltered terrain and wind slab activity on leeward alpine slopes. I'm confident the new snow will remain sensitive to human triggering for some time due to the presence of underlying surface hoar. Small avalanches have the potential to step down and trigger a persistent slab which would greatly increase the consequences of a release.

Snowpack Summary

Up to 25cm of new snow fell on Friday night. The new snow, which has been distributed into deeper deposits in higher wind-exposed terrain, overlies widespread 5-15mm surface hoar, a sun crust on steep sun exposed slopes, and/or wind affected surfaces in the alpine. The problematic mid-December surface hoar/crust layer is typically down 50-80cm below the surface and remains sensitive to human triggering is some areas. The reactivity of this persistent weak layer appears to be quite variable but still has the potential for large, destructive avalanches in some areas. The layer appears to be the most reactive at and below treeline.

Problems

Wind Slabs

An icon showing Wind Slabs
Up to 25cm of new snow fell and has been shifted into much deeper deposits in upper elevation lee terrain. Expect continued reactivity of the new snow due to underlying weak layers.
Use caution in lee areas in the alpine and at treeline. Wind loading has formed new wind slabs.>The new snow will require several days to settle and stabilize.>

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
The weight of the new snow, or an avalanche in motion, may be the tipping point for renewed destructive activity on weak layers which formed in December.
Use conservative route selection, stick to moderate angled terrain with low consequence.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Loose Dry

An icon showing Loose Dry
Watch for loose dry avalanches in steep sheltered terrain. Loose dry avalanches can pick-up mass quickly in gullies and other confined terrain features.
Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 17th, 2015 2:00PM

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