Avalanche Forecast

Issued: Dec 23rd, 2015 8:04AM

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

esharp, Avalanche Canada

Northwest Coastal.

A period of benign weather means avalanche conditions will not change significantly until the weekend. The best riding conditions can still be found in sheltered areas, but be mindful of the surface hoar buried around tree-line.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

We're looking at a period of fairly benign weather over Christmas before a powerful storm is forecast to hit the north coast. There may be some isolated flurries although not significant accumulations of new snow are expected through Friday. An artic front just inland will keep freezing levels at, or close to valley floor throughout the forecast period. Winds will be light and variable and on Thursday before becoming moderate westerlies by Friday.Â On Saturday everything changes.Â Coastal areas can expect to see up to 40 cm through the day while Terrace will receive more like 20.Â Freezing levels will rise to 1000 m and winds will build to extreme from the southwest through the day.

Avalanche Summary

No new avalanche have been reported. The lack of recent avalanche activity the buried layers of surface hoar don't mean they are not a problem. I suspect that as the new snow continues to settle we could start to see these layers wake up although it's difficult to predict when that will be.

Snowpack Summary

Sustained snowfall over the last several days has apparently made for awesome riding conditions. Cool temperatures have slowed the settlement of this new snow although light, variable winds have formed pockets of fresh wind slab on east through north-west aspects at tree-line and in the alpine. The recent storms have been incrementally adding load to a couple of week couple of buried persistent weak layers that we're tracking. There is now 25-40 cm above the December 17th surface hoar, and 35-55 cm above the December 14th surface hoar. Snow pit tests on Monday produced sudden failures on both of these layers. The December 1st surface hoar is now down a meter or so depending on your area. The distribution of this layer is variable. In some areas, it may still be sensitive to human triggering and capable of wide propagations, in other areas it is non-existent or has gained significant strength. Conditions may be different close to Kitimat, where it looks like recent snowfall amounts may be a bit higher and temperatures a bit warmer.

Problems

Wind Slabs

Variable winds will have formed deeper slabs in lee features on east through northwest aspects at higher elevations.

Be cautious as you transition into wind affected terrain.>Watch out for areas that may have been reverse loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

A couple of buried weak layer of surface hoar should be on your radar. I would be suspect of steep unsupported slopes at tree-line unless I knew the layer did not exist or was now well bonded.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 24th, 2015 2:00PM