Avalanche Forecast

Issued: Dec 20th, 2014 9:22AM

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

triley, Avalanche Canada

Sea To Sky.

Continued loading from new snow and strong winds will result in High avalanche danger in the alpine.

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Strong Southwest winds overnight combined with 15-20 cm of new snow and freezing levels rising up to about 1500 metres. Snow ending Sunday morning with a chance of flurries during the day with moderate Westerly winds. 3-5 cm of snow overnight Sunday into Monday morning combined with light Northwest winds. Unsettled with a chance of broken skies during the day on Monday. The next pulse of moisture should hit the coast on Tuesday, models are not in agreement on location and timing or intensity of the next storm.

Avalanche Summary

Explosives control released storm snow avalanches up to size 1.5 and some deeper avalanches that may have run on the November 28th buried crust (Deep persistent weak layer).

Snowpack Summary

A new storm slab is developing above the mix of current surfaces which include a mix of stubborn wind slabs and settled storm snow in the alpine, and a hard rain crust at lower elevations. Surface hoar growth has been reported in sheltered areas. There is still concern for a buried crust/facet layer which formed in November.

Problems

Storm Slabs

Storm slabs continue to develop with new snow and strong winds developing pockets of deep snow on lee terrain features.

Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Deep Persistent Slabs

Loading from the developing storm slab may overload the the deeply buried weak layer resulting in large avalanches.

Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Dec 21st, 2014 2:00PM