Avalanche Forecast

Issued: Dec 11th, 2014 8:23AM

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

pgoddard, Avalanche Canada

Sea To Sky.

Expect slowly improving conditions over the next few days.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Temperatures should start to fall on Friday and stay cooler through the weekend, with a freezing level around 900 m. 20-30 cm of snow is expected overnight Thursday/Friday, with a gradually lowering snow line. Winds become light for the weekend.

Avalanche Summary

Reports from Tuesday and Wednesday include numerous natural and explosives-triggered storm slab avalanches up to Size 2 at treeline and alpine elevations. Some of these stepped down deeper than 40 cm and propagated widely.

Snowpack Summary

Fluctuating freezing levels and heavy precipitation have generally resulted in rain-soaked snow that may form a hard crust extending as high as alpine elevations. Up to 40cm of fresh snow may be sitting atop this interface by Friday. If all goes well, we may experience a relatively quick healing process to take place within the storm snow, due to the forecast transition from wet and sticky to cooler, drier snow. However, you'll need to make your own (careful) observations to test this theory. In the high alpine, deep wind slabs and fragile cornices are likely to exist. Deeper snowpack weaknesses (e.g. crusts and facets) may be preserved at treeline and alpine elevations.

Problems

Storm Slabs

Recent storm and wind slabs may be susceptible to human triggering, especially on the northwest through northeast side of terrain breaks. A storm slab could trigger a more deeply buried weak layer, causing a surprisingly large avalanche.

Be alert to conditions that change with elevation and avoid wind loaded slopes near ridge crests.>Avoid exposure to terrain traps where the consequences of an avalanche could be serious.>Give the new snow a couple of days to settle and stabilize before venturing into exposed terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Dec 12th, 2014 2:00PM