Avalanche Forecast

Issued: Jan 12th, 2014 8:13AM

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

Avalanche Canada esharp, Avalanche Canada

The recent storm has loaded an unusually thin snowpack above a week layer near the ground. The "wait 48 hours and you're good" Coastal mantra does not apply right now as these conditions are likely to persist for some.

Summary

Confidence

Good

Weather Forecast

Tonight and Monday: Isolated flurries / Winds moderate to strong westerly / Freezing rising through the day up to 2000mTuesday: Cloudy / Winds moderate to strong westerly / Freezing continue to rise as high as 2500m.Wednesday: Clearing with sunny periods / Winds moderate to strong westerly / Freezing level 2500m.

Avalanche Summary

Most people were wisely avoiding the back country yesterday so we have not received a lot of observations from the Sea to Sky. Operations in neighboring regions reported a widespread natural avalanche cycle with numerous large to very avalanches. Some reports indicate isolated avalanches that are failing down on an old facet layer just above the ground.

Snowpack Summary

Saturday's storm clobbered the region with up to 100 cm of snow accompanied by strong winds (Whistler Blackcomb recorded gusts at ridge top up to 170km/h). The unrelenting southwest to south winds have formed large and touchy wind slabs in the alpine and at treeline. A widespread avalanche cycle has likely cleared out much of the surface hoar from early in January.The cold temperatures of early December left persistent weak faceted crystals that seem to be variably reactive. At higher elevations where the snowpack was deeper, the facets likely co-exist with a crust in the mid pack. At lower elevations or in shallow, rocky areas of the alpine, the facets are most likely more widespread and may exist down near the ground. Either way, the "wait 48 hours and you're good" Coastal mantra does not apply as these conditions are likely to persist for some time.In glaciated terrain open and poorly bridged crevasses are everywhere although now they are hiding under a meter of unsupportive storm snow.

Problems

Storm Slabs

An icon showing Storm Slabs
Give the snow some time to settle before getting onto steeper terrain. Recent winds have been strong to extreme to so expect to find windslab extending far down or across lee features.
The new snow will require several days to settle and stabilize.>Enter your line well below ridge crests to avoid wind loaded pillows.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
On the surface things are looking more "normal" but remember that in places the new snow is sitting on a weak and thin midpack. Knowing the terrain is becoming increasingly critical. Avoid slopes that were shallow and rocky before this last storm.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Choose the deepest and strongest snowpack areas on your run.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Jan 13th, 2014 2:00PM