Avalanche Forecast

Issued: Feb 21st, 2017 3:35PM

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

mgrist, Avalanche Canada

South Columbia.

The best riding right now is probably on high north aspects, which is also where the hazard is the highest. Don't let your guard down when searching for fresh powder.If the sun comes out in full force, use extra caution on south slopes.

Summary

Confidence

Moderate - The weather pattern is stable

Weather Forecast

We're into a stable and benign weather pattern with cooling temperatures and isolated flurries.WEDNESDAY: Cloudy with light flurries (local accumulations 5-10cm possible) / Light northerly winds / Freezing levels around 700 m.THURSDAY: Cloudy with sunny breaks and isolated flurries / Light southerly winds / Freezing level 400m / Alpine high temperatures near -5 Celsius.FRIDAY: A mix of sun and cloud and isolated flurries / Light variable winds / Freezing level 300m / Alpine high temperatures near -5 Celsius.

Avalanche Summary

On Monday we had reports of a couple of skier-triggered Size 1.5 storm slab avalanches (20-35 cm thick) on a variety of aspects near 2100m elevation. Natural wind slab activity (to Size 2) was reported on Sunday up near 2200m on steep east and northwest aspects in this region.A couple of skier-triggered wind slab avalanches (to Size 1.5) were reported on steeper (38 degree) north or northwest aspect slopes near 2100m on Saturday. Wind slabs at higher elevations are sensitive to light triggers and have the potential to step down and trigger persistent slab avalanches.

Snowpack Summary

We've had modest snowfall amounts (15-30cm) over the past several days, with moderate southeasterly winds in some locations. Expect to find 35-50 cm of more recent snow bonding slowly to buried Feb 15th surface hoar and/or a crust, and blown into wind slabs at higher elevations. In some areas of the Monashees, snow pack tests are giving easy sudden planar results on southerly aspects around 2000m on the Feb 15th surface hoar layer (down 45cm) above a sun crust.The sun is starting to pack a punch and can trigger loose snow avalanches mid-day. The sun is also creating a thin crust on steep southerly aspects.Below 1500m a frozen rain crust is mostly supportive, but up to 1800m it can be breakable. Storm snow from last week is still bonding slowly to the previous snow surface from early February, which is now down 60-80 cm. The mid and lower snowpack are generally well settled and stable in deeper snowpack areas but may be faceted and weaker in shallower areas.

Problems

Wind Slabs

Wind slabs are still lurking below ridge crests and behind terrain features at higher elevations. Choose your line carefully and use ridges or ribs to avoid pockets of wind slab.

Use caution in lee areas. Recent wind loading have created wind slabs.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

A persistent weakness down 50-80 cm remains remains sensitive to light triggers in isolated areas. Smaller avalanches have the potential to step down to this layer.

Be aware of the potential for large avalanches due to the presence of buried weak layers.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Feb 22nd, 2017 2:00PM