Avalanche Canada triley, Avalanche Canada

Sea to Sky Avalanche Forecast

Dec 10th, 2012 9:44AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs.



Fair - Intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Overnight and Tuesday: 10-15 mm of precipitation is forecast to start Monday evening and then ease to light in the afternoon. Strong Westerly winds are expected overnight and during the morning. The ridge top temperature should be -6.0 and the freezing level at 1000 metres.Wednesday:Some very light precipitation in the morning that should end by afternoon. Light variables winds in the morning should become moderate Northerly in the afternoon. Freezing level should drop down to the valley overnight and then rise to 800 metres during the day.Thursday:Another frontal system is lining up to hit the North Coast on Thursday and then start to move down to the South. Timing is unsure for this system.

Avalanche Summary

Some thin wind slabs were ski cut up to size 1.0 that were 20 cms deep. Explosives control released a size 2.0 in steep un-skiable terrain.

Snowpack Summary

Some exposed areas have developed a thin stiff wind slab in the alpine. Sheltered areas have 20-30 cms of light unconsolidated snow above a gradually stiffening snowpack. Snowpack tests have not been showing any consistent results in the storm snow. Foot penetration may still be up to 70 cms as the wind slab is not able to carry the weight of a person without skis. Professionals are concerned about the early November rain crust. If this deep persistent weak layer (DPWL) becomes reactive, the consequences will be very large destructive avalanches. The crust may be buried between 100-200 cms depending on the total depth of the snowpack in your area. The crust may be a bigger problem where it has a layer of facetted crystals above, rather than where it is like a laminated sandwich of crusts and facets. If that sounds too technical for you, then the take home is that this is not an easy problem to gauge when or where it might wake up.


Wind Slabs

An icon showing Wind Slabs



Expected Size

2 - 5
Wind slabs are expected to continue to build due to strong Westerly winds and moderate precipitation amounts.
Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>


North, North East, East, South East.


Alpine, Treeline.

Valid until: Dec 11th, 2012 2:00PM