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Archived

Avalanche Forecast

Dec 19th, 2014–Dec 20th, 2014
Alpine
4: High
The avalanche danger rating in the alpine will be high
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
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
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.

Avalanche danger rising to HIGH as the storm slab continues to develop.

Confidence

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

Weather Forecast

Entering a very stormy period for the North Coast. Very strong Southerly winds overnight and during the day on Saturday. 15-25 cm of snow tonight above 600 metres elevation. Another 15-25 cm during the day on Saturday as freezing levels rise up to at least 1000 metres and maybe as high as 1400 metres in some areas. Winds decreasing to strong by Sunday morning with another 10-15 cm expected and a further 10-15 cm during the day. Monday should be drier with Westerly winds and dropping freezing levels.

Avalanche Summary

No new avalanches reported. The forecast new storm is expected to increase avalanche activity over the next few days.

Snowpack Summary

A new storm slab is developing above the recent mix of surfaces which include wind slabs in alpine terrain, hard rain crusts at lower elevations and weak surface hoar crystals. Last week's heavy rain affected southern parts of the region up to alpine elevations, while the far north remained drier and generally has a weaker snowpack. Areas which previously received rain have probably now formed a hard frozen crust. Upper elevation terrain and far northern areas are likely to have wind slabs and large fragile cornices. Deeper in the snowpack, weaknesses such as the mid-November crust-facet layer still exist. Avalanches at this interface have become unlikely, although the consequences of a release remain high. This layer may be more sensitive to triggering in steep, unsupported high alpine terrain, or in the far north of the region.

Avalanche Problems

Storm Slabs

Continued new snow should add to the developing storm slab. This slab is expected to consolidate and allow for longer propagations resulting in larger avalanches.
Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>Avoid freshly wind loaded features.>Cornices may be large and fragile with new growth. Stay well to the windward side of corniced ridges, and avoid travelling beneath cornices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4