Avalanche Forecast

Issued: Mar 4th, 2013 9:34AM

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

triley, Avalanche Canada

Cariboos.

Summary

Confidence

Good

Weather Forecast

Synopsis: A ridge of High pressure over the Eastern Pacific will provide a mix of sun and clouds with some chance of light precipitation for the next 2-3 days. Winds are expected to be light Northeasterly and alpine temperatures should be around -11.0.

Avalanche Summary

Natural avalanches were observed up to size 3.0 on various aspects in the alpine and at the treeline. Explosives controlled avalanches were reported up to size 3.5 from various aspects in the alpine. Some cornice fall was reported up to size 2.0, and one snow-machine accidental avalanche was reported to be size 3.0 from a North aspect at about 1700 metres elevation.

Snowpack Summary

The Caribous picked up an extra 20 - 40 cm Saturday night which brings the recent storm total to 60 - 100cm. Strong winds out of both the SW and more recently NW have formed wind slabs on lee aspects in the alpine and wind exposed treeline elevations. The weak Feb. 12 surface hoar layer is now down 100 - 150 cm. This layer along with a deeper weak layer from late January continue to show planar failures when moderate to hard forces are applied in snow pack tests.

Problems

Storm Slabs

Human triggering remains a concern as the snowpack adjusts to it's new load. Storm slab avalanches have the potential to step down to the buried surface hoar resulting in large destructive avalanches.

The new snow will require several days to settle and stabilize.>Good day to make conservative terrain choices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 6

Cornices

The storm has left many large cornices in it's wake on lee slopes, many of which may be teetering on the brink of failure. Cornice fall has the potential to initiate large destructive avalanches.

Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

A weak layer of surface hoar and/or a crust is now down 100 - 150 cm. The coming days will reveal more about the sensitivity of this layer, but it's still suspect at the present time.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 7

Valid until: Mar 5th, 2013 2:00PM