Avalanche Forecast

Issued: Jan 27th, 2016 8:00AM

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

triley, Avalanche Canada

Cariboos.

Warm, Wet, and Windy storm will create new wind slabs and add load above the persistent weak layer. Conservative terrain use recommended at this time.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Freezing levels are uncertain overnight. Most products are suggesting that freezing levels will rise up to about 1700 metres, however there is a chance that freezing levels may rise as high as 2200 metres. This is more likely in the west of the region. Expect 5-8 cm of new snow in the alpine overnight combined with strong southerly winds. New snow and strong southerly winds are forecast to continue during the day on Thursday resulting in 10-15 cm. Freezing levels dropping Thursday night down to about 1000 metres by Friday morning. Light snow and light southerly winds on Friday. Light winds and flurries on Saturday combined with continued cooling.

Avalanche Summary

No new avalanches reported. One size 1.5 natural avalanche was reported on Monday. On Sunday, a skier remotely trigger a size 1 avalanche on a NW aspect from 10m away. The slab was 60cm thick which suggests that it failed on the early January surface hoar layer. Natural loose avalanches up to size 2 were also reported from extreme terrain and did not trigger any slabs below. Widespread natural avalanche activity up to size 3 was reported on Friday and Saturday.

Snowpack Summary

New wind slabs are developing in the alpine and at treeline. Wind slabs and recent storm slabs have added load and stress to the already volatile persistent slab. There are a couple of highly reactive layers of surface hoar typically down 70-100cm which have been responsible for numerous recent large avalanches. The persistent slab is ripe for human and natural triggers and is especially touchy at and below treeline. The mid and lower snowpack below these layers is generally well-settled and strong, with any old weak layers considered dormant for now. Snowpack depths are variable and shallow snowpack areas may have weak facetted crystals near the ground.

Problems

Wind Slabs

New wind slabs should continue to develop with forecast strong southwest winds and new snow. Thin new storm slabs may develop in sheltered terrain.

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The slab above the persistent weak layer continues to be touchy, releasing naturally or with light additional loads like a single skier on adjacent terrain. Conservative terrain choices without overhead hazard are recommended at this time.

Use conservative route selection and be aware of the potential for remote triggering. >Extra caution required in open terrain features at and below treeline. >Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Jan 28th, 2016 2:00PM