Avalanche Forecast

Issued: Jan 13th, 2014 8:53AM

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

South Coast.

Local avalanche conditions differ greatly across the region. In areas where until recently the snow pack has been unusually it is possible to trigger large and destructive avalanches. Now is a good time to make conservative terrain choices.

Summary

Confidence

Good

Weather Forecast

Synopsis: A clearing trend as a warm ridge builds over the region causingÂ rising freezing levels.Â 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 / 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 wester / Freezing levels 3000m

Avalanche Summary

We've receive reports confirming a widespread natural avalanche cycle that ran through the weekends storm. Several large avalanches were observed in the north of the region that released at or close to the ground, confirming our suspicions of a deep persistent slab problem. There have also been several recent close calls with human triggered soft slab avalanches in Coquihalla region: a good reminder that although the avalanche problems in the south may be easier to manage storm and wind slabs are lingering.

Snowpack Summary

The weekends storm clobbered the region with between 80-100cm of new snow. Sustained moderate to strong south to southwest winds have created thick and reactive winds slabs extending far into lee features. In the north of the region, the storm snow fell onto a week layer of surface hoar from earlier in the month. In areas with a shallow or rocky snowpack facets exist immediately above the ground.Although on the surface things are starting to look more normal, it is important to remember that the new snow is sitting on a thin and weak midpack. 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 the south of the region where the early season snowpack was deeper these persistent weak layers do not seem to be as prevalent.Snowpack depths at treeline range from 150-250 cm in the south, and from 90- 150 cm in the north. In glaciated terrain open and poorly bridged crevasses are everywhere although they are now hiding under a meter of unsupportive storm snow.

Problems

Deep Persistent Slabs

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

Choose the deepest and strongest snowpack areas on your run.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Whumpfing is direct evidence of a buried instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Wind Slabs

Warming temperature will encourage settlement of the storm snow. However, expect reactive pockets of winds slab extend far into lee features. In the north of the region storm snow may be sitting above surface hoar.

Use ridges or ribs to avoid pockets of wind loaded snow.>Enter your line well below ridge crests to avoid wind loaded pillows.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

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