Avalanche Forecast

Issued: Jan 1st, 2016 8:12AM

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

bcorrigan, Avalanche Canada

Purcells.

Travel with care in the backcountry. Riders have triggered 2 large avalanches west of Kimberly and 1 near Golden in the past week

Summary

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

A modified, dry arctic air mass remains over the much of the province. Expect valley fog in the morning at lower elevations and sunshine in the alpine for most of the interior of BC. Moderate temperatures aloft, with above freezing layers of warm air, will pass through the Province during the weekend.For more in-depth weather information, check out: http:www.avalanche.ca/weather

Avalanche Summary

On Thursday, a skier triggered a size 2.5 slab on a NW aspect at about 2500 m near Golden. It is thought to have failed on the early Dec. persistent weak layer, down 30-60 cm. There has also been activity clustered in a region to the west of Kimberley. On Tuesday, a skier triggered a size 2 persistent slab. Last Sunday, a skier triggered a size 3 slab. Skiers also remotely triggered a size 2 slab the week before. These all failed on the early December surface hoar layer and were on all aspects between 1600 m and 2100 m. Small loose dry avalanches and cornice falls have also been reported.

Snowpack Summary

Conditions are variable across the Purcells. In the south (west of Kimberley), a prominent layer of large buried surface hoar is reactive to human triggers. In this part of the region, it is buried down 40 cm with a cohesive slab above it. Further north, it is 60-120 cm down and has been sporadically reactive to skiers on NW facing alpine slopes near Golden. At alpine elevations, this interface exists as a surface hoar/ facet layer sitting on a crust. The lower snowpack is generally considered to be well settled.New and old wind slabs may be found in the lee of ridges and ribs on a variety of slopes.

Problems

Persistent Slabs

Skiers have triggered four large persistent slab avalanches in the last couple of weeks. The culprit is surface hoar from early December down 40-60 cm. It exists at different elevations in parts of the region, but it is definitely out there!

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved, especially in the south of the region.>Avoid exposed alpine faces, especially in the north of the region.>Dig down to find and test weak layers before committing to a big line. >Avoid slopes with glide cracks.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Loose Dry

Warm upper elevation temperatures combined with strong solar effect set the stage for loose sluffs out of steep terrain. These could be big enough to injure or bury a rider.

Minimize exposure to steep sun exposed slopes when the solar radiation is strong. >Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >Be aware of party members below you that may be exposed to your sluffs. >

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Recent changes in wind direction will have given us both soft and hard wind slabs on most aspects, pay close attention as you transition into new terrain, especially at tree line and above.

Use ridges or ribs to avoid pockets of wind loaded snow. >Be cautious as you transition into wind affected terrain. >

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 2nd, 2016 2:00PM