Avalanche Forecast

Issued: Dec 24th, 2017 4:45PM

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

Avalanche Canada jmcbride, Avalanche Canada

Looks like good ol' Saint Nick will be delivering a dusting of new snow for Christmas morning.  Hopefully he will give up the rest of the goods later in the week and spread a bit more of that festive spirit.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

A light dusting (2-5 cm) on new snow is expected late Sunday and early Monday morning.MONDAY: Mix of sun and cloud, light flurries. Accumulation trace. Ridge wind light from the northwest. Temperature -6. Freezing level surface.TUESDAY: Mix of sun and cloud. Ridge wind light from the southwest. Temperature -8. Freezing level surface.WEDNESDAY: Cloudy, flurries. Accumulation trace. Ridge wind light to moderate from the west. Temperature -5. Freezing level surface.

Avalanche Summary

There have been no reports of avalanche activity since Thursday when there was a report of a small (size 1) skier accidental wind slab release on a north aspect in the alpine. On Wednesday, several small, skier-triggered avalanches were reported as well as explosives triggered slab avalanches up to Size 3 on wind-loaded slopes in the alpine and at treeline. See here and here for recent Mountain Information Network (MIN) reports.

Snowpack Summary

The recent storm snow has been redistributed by strong northerly winds scouring windward, north to west aspects and building wind slabs on leeward, south to east aspects in the alpine and exposed treeline areas. This has created a highly variable upper snowpack with areas of both soft snow and hard wind slab, as well as areas of exposed crust depending on aspect and elevation. An average of 20-40cm of settled storm snow now sits on a melt-freeze crust (December 15th layer) that formed on all aspects and elevations. On high north aspects this crust is thin with dry, sugary snow crystals (facets) below. Below the December 15th layer, the late November crust is now buried 70-100 cm with a thin layer of facets above. Beneath this crust the lower snowpack is well settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind affect at upper elevations is highly variable with both soft and hard wind slab on leeward slopes slopes and exposed treeline areas. These may still be reactive to light loads such as a skier or rider.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious as you transition into wind affected terrain.Watch for whumpfing, hollow sounds, and shooting cracks.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 25th, 2017 2:00PM

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