Avalanche Forecast
Issued: Jan 3rd, 2012 9:44AM
The alpine rating is Wind Slabs, Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Good - -1
Weather Forecast
An intense storm will bring moderate to local heavy amounts of precipitation-expect around 15-20 mm Tuesday night and a further 5-15 mm on Wednesday. Freezing levels will rise to around 1500 m and then start to fall on Wednesday afternoon as a cold front passes over. The passage of the cold front is unlikely to bring only light precipitation to inland areas, say 5 mm. Ridgetop winds will be extreme (up to 140 km/h) initially from the southwest, then becoming westerly. On Friday, another frontal system hits the north coast; however it looks as though northwest inland areas will be influenced by a ridge of high pressure keeping things mainly dry and cold.
Avalanche Summary
High winds and poor visibility have limited observations for the last few days; however, no activity has been reported to us from this region recently. I suspect you could easily trigger a pocket of wind slab on exposed lee terrain and I'd still be nervous of triggering the mid-December surface hoar layer down around 70 cm in sheltered locations.
Snowpack Summary
New snow and strong winds have set up fresh wind slabs mainly on north through east aspects in exposed lee terrain--these are likely triggerable by riders on sleds or on skis. 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.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 4th, 2012 8:00AM