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Archived

Avalanche Forecast

Dec 11th, 2013–Dec 12th, 2013
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

Strong winds and heavy snowfall are expected to increase the Danger to HIGH by morning.

Confidence

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

Weather Forecast

Overnight and Thursday: A strong pulse of Pacific moisture will continue to bring snow overnight, with 20-30 cm accumulating by morning. Snowfall should moderate during the day, another 10-15 cm is forecast. Strong Southwest winds overnight should gradually become moderate during the storm. Freezing level about 1000 metres.Friday: There should be a bit of a lull in the storm before the next pulse comes on-shore Friday evening. Expect flurries and light to moderate Westerly winds during the day, increasing to heavy snowfall and strong Southwest winds in the evening. Freezing level dropping below 700 metres.Saturday: 20-30 cms of new snow by Saturday morning with strong Southwest winds and rising freezing levels.

Avalanche Summary

The warm new storm snow is not expected to bond well to the shallow weak snowpack. Expect natural avalanche activity and easy triggering from skiers and sledders.

Snowpack Summary

New storm slab is 30 cm deep and growing. Strong Southwest winds are transporting snow and developing deep pockets that are sitting above recent weak surface layers. Rising temperatures during the storm are expected to develop a relatively warm storm slab above a cold layer of wind crusts, surface hoar and surface facets. Snow profile information from the Shames area on Monday before the storm on a South-Southwest aspect at 950 metres, showed a 70 cm base with loose snow in the top 20 cms above a stiff 4 cm crust that is sitting above a softer facet layer. There was another hard crust about 30 cms above the ground. The new storm is a great deal of change for this young and weak snowpack to handle.

Avalanche Problems

Storm Slabs

The warm new storm snow is expected to release naturally and may be very easy to trigger by skiers and sledders. As the storm slab builds expect large avalanches.
Minimize exposure during periods of heavy loading from new snow, wind.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 2 - 5