Avalanche Forecast

Issued: Feb 25th, 2013 10:06AM

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

jlammers, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to variable weather conditions

Weather Forecast

Tuesday: Trace amounts of new snow / Moderate southwest winds / Freezing level at 800mWednesday: Light snowfall / Light southwest winds / Freezing level at 900mThursday: Light snowfall / Moderate southwest winds / Freezing level at 1400m

Avalanche Summary

In recent days 2 skier-triggered avalanches were reported having failed on the February 12th surface hoar. For more information, go to our Incident Report database. On Monday a few size 2-2.5 natural slab avalanches were observed on the Coquihalla. Explosives control in the Duffey Lake area produced avalanches of similar size.

Snowpack Summary

Light snowfall on the Duffey and heavy snowfall on the Coquihalla has been redistributed into wind slabs at treeline and above. The new snowfall puts weak surface hoar buried on February 20th up to 70cm below the surface. Where it exists, the surface hoar will likely prolong the reactivity of the recently developed storm slab.On shaded slopes up to 60cm of snow may overlie surface hoar which was buried on February 12th. Most reports of this layer are coming from the Duffey Lake area where observations include whumfing and easy, sudden planar test results. On solar aspects and at lower elevations recent accumulations overlie a series of melt freeze crusts.The mid and lower snowpack pack layers are generally well settled.

Problems

Storm Slabs

A storm on Monday will add to ongoing storm/ wind slab conditions, especially in the south of the region. Triggering avalanches will be most likely in wind-loaded terrain, or in more sheltered areas where weak and reactive buried surface hoar exists.

The new snow will require several days to settle and stabilize.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Persistent Slabs

A weak layer of surface hoar buried on February 12th continues to react to skier triggering, particularly in the north of the region. See the forecast details page for recent incident reports.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Feb 26th, 2013 2:00PM