Avalanche Forecast

Issued: Jan 13th, 2014 8:49AM

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

esharp, Avalanche Canada

Sea To Sky.

We're dealing with an unusual snowpack right now on the Sea to Sky. Check out the recent Forecasters Blog post for a more detailed discussion

Summary

Confidence

Good

Weather Forecast

Synopsis: A clearing trend as a warm ridge builds over the region causing rising freezing levels. There is the possibility for some light precipitation Tuesday night as a cold front slides down the coast although this front will not displace the warm air.Tonight and Tuesday: Cloudy with sunny periods / 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.Thursday: Sunny / Winds light westerly / Freezing levels 3000m

Avalanche Summary

We've receive reports confirming a wide spread natural avalanche cycle that ran through the weekends storm. Importantly several large avalanches were observed to have released at or close to the ground, confirming a deep persistent slab problem exists in the region.

Snowpack Summary

Last weekends storm clobbered the region with up to 100 cm of snow. This fell on a couple of layers of surface hoar found in sheltered terrain at and below treeline. The unrelenting southwest to south winds have formed large and touchy wind slabs in the alpine and at treeline.Although on the surface things are starting to look more a little more normal than they have it is important to remember that this latest snow fell on a fundamentally thin and weak snowpack. 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. At lower elevations or in thin, rocky alpine features more widespread facets exist down near the ground. This makes for a low probability high consequence avalanche scenario that is more commonly associated in the interior of the province. 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

Deep Persistent Slabs

Recent avalanche activity confirms that weak and reactive layers are lurking deep in the snow pack. Avoid slopes that were shallow and rocky before this last storm. Don't let improving riding conditions tempt you into bigger terrain.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Be aware of thin areas that may propogate to deeper instabilites.>Choose the deepest and strongest snowpack areas on your run.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Wind Slabs

Warming temperature will encourage the settlement of the storm snow. However, expect reactive pockets of winds slab to extend far into lee features. At and below treeline wind slabs may be sitting above surface hoar.

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

Expected Size

2 - 5

Valid until: Jan 14th, 2014 2:00PM