Avalanche Forecast

Issued: Jan 18th, 2013 9:34AM

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

jlammers, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Only trace amounts of new snow (possibly higher amounts on Monday in the North) are expected for the forecast period. Winds should remain mainly light to moderate from the southwest with freezing levels hovering between 800-900m.

Avalanche Summary

Due to inclement weather observations have been very limited; however, numerous moist or wet snow avalanches to size 2.5 were reported from the region on all aspects at treeline and below. On Thursday numerous avalanches ran to size 3.5 in the north of the region where recent snow accumulations were the highest. They occurred in response to heavy snowfall and strong to extreme winds.

Snowpack Summary

Rain below treeline has maintained moist snow at lower elevations, although a nightly crust recovery is likely with forecast clear skies. Light amounts of new snow (moderate to heavy amounts in the north) exist as new storm slabs and windslabs at treeline and above. A persistent weakness of surface hoar or facetted snow buried at the end of December sits below all of the more recent storm snow and is still on the radar of professionals in the area. The mid and lower snowpack is generally well settled and strong, although well developed basal facets remain a concern in shallow snowpack areas.

Problems

Wind Slabs

Strong to extreme westerly winds have continued to create touchy wind slabs in exposed lee and cross-loaded terrain at higher elevations. Heavy accumulations in the north have created a very destructive storm/ windslab instability.

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 6

Loose Wet

Rain at lower elevations is maintaining a weak snowpack. Watch for triggering in steep start zones.

Watch for wet loose or slab activity with continued warm temperatures at lower elevations.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

There has been no new activity reported on this layer. Having said that, the weakness still exist with the potential to produce large avalanches.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Jan 19th, 2013 2:00PM