Avalanche Forecast

Issued: Jan 7th, 2014 8:38AM

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

jlammers, Avalanche Canada

South Coast.

Forecast snowfall amounts are highly variable throughout the region with the southern areas expecting the see the highest accumulations. Pay attention to local conditions.

Summary

Confidence

Fair - Track of incoming weather systems is uncertain on Wednesday

Weather Forecast

Overview: The jet stream will flatten out allowing a series of pacific systems to impact the region with the south seeing the highest accumulations.Wednesday: Moderate snowfall / Moderate southwest winds / Freezing level at 1200mThursday: Moderate to locally heavy snowfall with the most intense precipitation falling late in the day / Strong to extreme southwest winds / Freezing level at 900mFriday: Moderate snowfall / Moderate to extreme westerly winds / Freezing level at 1200m

Avalanche Summary

2 size 2 slab avalanches (human triggered and natural) were observed in Marriott Basin in the Duffey Lake area over the last few days. No injuries were reported. The avalanches occurred around 2100m on south-facing terrain. Both were thought to have ran on a crust/facet interface. Check out our Incident Report Database for more details.

Snowpack Summary

Snowpack depths at treeline range from 130-170 cm in the South of the region, and from 80- 130 cm in the North of the region. Light amounts of new snow overlie a variety of old surfaces which may include surface hoar in sheltered terrain, wind-pressed snow in exposed areas, or a crust on previously sun-exposed slopes.In the north of the region, recent storm snow is sitting on weak layers of buried surface hoar which formed in early December. Facets from December's cold snap also seem fairly widespread in this part of the region. In some areas, these facets may co-exist with a crust. In thin snowpack areas, the facets may exist at ground level. These persistent weaknesses may likely wake-up with new snow forecast for the rest of the week.

Problems

Storm Slabs

Snowfall throughout Wednesday will build new and potentially reactive storm slabs. Watch for increased reactivity in wind-exposed terrain.

Be alert to conditions that change with elevation.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Snow forecast for the week will create a steadily increasing load to buried persistent weakness which seem most prevalent in the north of the region. Triggering these weaknesses may have nasty consequences.

Dig down to find and test weak layers before committing to a line.>Use caution in shallow snowpack areas where triggering is more likely.>Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 8th, 2014 2:00PM