Avalanche Forecast

Issued: Jan 9th, 2013 9:41AM

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

Avalanche Canada mpeter, Avalanche Canada

Although the danger has dropped to CONSIDERABLE, a very cautious approach is imperative. The mountains have hit the reset button and we need to do the same with our expectations of what is safe to ride.

Summary

Confidence

Fair

Weather Forecast

Thursday: Expect mixed skies with some sunny breaks later in the day. Temperatures should reach -10 and winds turn to light northerlies.Friday & Saturday: A ridge dominates giving mixed skies, light northerly winds and cool alpine temperatures. Valley cloud is possible.

Avalanche Summary

Avalanches up to 2.5 have been reported, predominantly windslabs failing naturally and with explosives in lee locations. Isolated rider triggering has also been reported.

Snowpack Summary

The recent storm has brought up to 60cm of snow. Consistent southwest winds have redistributed the new snow (dramatically in some areas) to create widespread windslabbing on lee and open features in the alpine and exposed treeline. Where the wind has been strongest, windslabs are much lower on slopes than normal.There have been avalanches reported both within the storm layers as well as at the initial storm interface, the January 4th layer. This layer consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds with the facetted snow are improving while the surface hoar &/or sun crust interface is weak. There are reports of Sudden Planar shears (fast & clean) in compression tests and “Propagation Likely” results in extended column tests on the preserved surface hoar.The midpack is well bonded and strong. The November 28 surface hoar is still being found in isolated, sheltered below treeline locations buried 120cm. The deep crust/facet combo from early November still exists and concern remains (although unlikely) for triggering this layer from a shallow spot or with a heavy load.

Problems

Storm Slabs

An icon showing Storm Slabs
Rapid settlement is creating a cohesive storm slab
The new snow will require several days to settle and stabilize.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Wind Slabs

An icon showing Wind Slabs
New windslabs have formed in immediate lee and cross loaded locations. The winds are strong, meaning more intense slab development and slabbing extending lower on the slopes than normal.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 6

Valid until: Jan 10th, 2013 2:00PM

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