Avalanche Forecast

Issued: Feb 19th, 2015 7:12AM

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

Peter, Avalanche Canada

Cariboos.

Hazard is low; however, give cornices respect when travelling in the alpine. They are a stand-alone hazard but could also be a potential trigger for deep slabs.

Summary

Confidence

Good

Weather Forecast

We should see a couple more days of mainly cloudy skies with light flurries before the ridge of high pressure rebuilds returning the province to sunny conditions by late Saturday or Sunday. The freezing level is around 1300 m on Friday and lowers to just under 1000 m on the weekend. Winds are light gusting to moderate from the NW on Friday and switch to north-easterly for the weekend.

Avalanche Summary

On Tuesday and Wednesday a couple natural and explosive triggered cornice falls were reported. These were size 2-2.5 and some triggered slabs on the slopes below while others did not. Neighboring regions reported similar activity with cornice fall and isolated deep slabs being the main concern.

Snowpack Summary

The snow surface is a mix of surface hoar, crusts, 10-25 cm of low density snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. At alpine elevations, new wind slabs may have formed from NW winds, and cornices are large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) continue to give variable results in snowpack tests. Chances of triggering these weaknesses have decreased, but triggering may be possible from thin or rocky snowpack areas; or perhaps with a cornice fall, or an avalanche stepping down, especially on sun drenched slopes.

Problems

Wind Slabs

Pockets of wind slab may still be reactive in steep lee terrain or cross-loaded gully features in the alpine. Cornices are large and potentially weak and should be given a wide berth.

Give cornices a wide berth when travelling on or below ridges.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Buried persistent weaknesses are largely dormant but could still be triggered by a large load (i.e. cornice fall) or from areas with a shallow or variable snowpack.

Avoid steep slopes below cornices.>Avoid common trigger spots, including convexities or areas with a thin or variable snowpack.>

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

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Feb 20th, 2015 2:00PM