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Archived

Avalanche Forecast

Jan 6th, 2012–Jan 7th, 2012
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
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 Inland.

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

An intense storm with a southern moisture feed (a Pineapple Express) is due to hit this region this weekend, bringing around 10 cm new snow on Saturday and 20 mm rain/snow on Sunday. Freezing levels should start out around 700 m Saturday and spike sometime Saturday night/Monday morning at up to 1800 m. Flurries may continue into Monday, freezing levels will gradually lower to valley bottom by the end of the day Monday.

Avalanche Summary

A natural avalanche cycle up to size 2 was reported from the region on Wednesday affecting all aspects.

Snowpack Summary

Recent new snow and strong winds have set up fresh wind slabs at higher elevations, mainly on north through east aspects in exposed lee terrain--these are likely triggerable by riders on sleds or on skis. Lower down, a rain crust exists up to approximately 1000 m. There is now approximately 80 to 120cms of storm snow sitting above a surface hoar/crust/facet layer that was buried mid-December. The increasing depth of this weak layer makes it difficult to trigger; however, I wouldn't ignore this layer yet, as it could still be triggered by large loads such as rapid loading by new snow or rain or cornice falls. It could also be triggered by riders in shallow snowpack areas or where rocks poke up near the surface. The mid- and lower snowpack layers are well consolidated and generally strong.

Avalanche Problems

Storm Slabs

New snow with rising temperatures will set up storm slabs on steep, open slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 5

Wind Slabs

Strong southwesterly winds have set up touchy wind slabs on mainly north through east aspects.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 6

Persistent Slabs

Persistent slabs are getting harder to trigger but still exist in many locations. The probability of triggering will go up if rain starts to affect higher elevations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 6