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Avalanche Forecast

Dec 18th, 2015–Dec 19th, 2015
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

Incremental loading of new snow and wind over variable buried weak layers will trend the avalanche danger up. Watch for clues like whumphing settlements and evidence of natural activity on steep wind exposed terrain.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

Flurries and light snow overnight with moderate south west winds and freezing levels at valley bottoms. Snow beginning Saturday morning with increasing southwest winds, expect 10-15 cm during the day. Another 10-15 cm is expected by Sunday morning, with more possible in the south near Kitimat as the storm center looks to pass just to the south of the region. Incremental loading should continue on Sunday with another 5-10 cm and 10-15 by Monday morning.

Avalanche Summary

No new avalanches reported. Extensive wind effect reported in the alpine and at treeline.

Snowpack Summary

New snow continues to slowly build the load above buried weak layers. There is 15-25 cm above the December 17th (151217 SH) surface hoar, and 25-40 cm above the December 14th (151214 SH). At this time, the new snow continues to come in cold and dry and may not have the load needed to settle into a cohesive slab above these weak layers. The early December layer buried on the 1st or 2nd (151201 SH) is now down a metre or so depending on your area. This layers distribution is variable. In some areas, this layer may be sensitive to human triggering and wide propagations while in other areas it is non-existent or has gained significant strength.  Most of this information is coming from the Shames area or from commercial operations near Terrace. Conditions may be different close to Kitimat, where it looks like recent snowfall amounts may be a bit higher and temperatures a bit warmer. The north of the region has a shallow early season snowpack and may have weak facetted crystals near the ground due to cold temperatures over a thin snowpack.

Avalanche Problems

Storm Slabs

New storm slabs have developed in the alpine and at treeline. Pockets of wind transported snow may be deep due to strong winds during the storm.
Be cautious as you transition into wind affected terrain.>Travel on ridgetops to avoid wind slabs on slopes below.>Stay well to the windward side of corniced ridges.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

Areas with buried surface hoar down around 100 cm may continue to be triggered by light loads in weak spots around exposed rocks or trees. This layer of buried surface hoar is variable across the region.
Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 2 - 4