Avalanche Forecast

Issued: Dec 26th, 2018 3:00PM

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

ghelgeson, Avalanche Canada

North Columbia.

Large human triggered avalanches remain possible. At these times it's less about snow and more about human factors. The bold will push into bigger lines, those with lower risk threshold will be content with more conservative terrain. Fx'r blog here.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

Enjoy the brief lull in the weather Thursday and Friday, it looks like we will be right back into the storm track this weekend. What happens beyond that is a bit uncertain, but a ridge of high pressure will likely take us into the New Year.WEDNESDAY NIGHT: Freezing level at valley bottom, light variable wind, trace of snow possible. THURSDAY: Broken cloud cover, freezing level at valley bottom, light northerly wind with moderate gusts near ridgetop, no significant precipitation expected. FRIDAY: Scattered clouds at dawn with cloud cover building through the day, freezing level at valley bottom, light southwest wind at valley bottom with moderate west/southwest wind in the alpine, a few centimeters of snow possible during the day. 5 to 10 cm of snow Friday night.SATURDAY: Overcast, freezing level beginning at valley bottom, rising to around 1600 m by sunset. Strong southwest wind, 10 to 15 cm of snow.

Avalanche Summary

No new avalanche activity to report from Tuesday aside from minor sluffing. Monday was similar with riders triggering small loose dry avalanches in steep terrain as the storm snow sluffed away. A brief appearance of the sun also induced small loose dry avalanches.A few small dry loose avalanches and wind slabs were reported in the most recent snow on Sunday. On Saturday, a few large (size 3) avalanches were triggered by explosives on south-facing alpine slopes. The avalanches released on persistent weak layers 60-150 cm deep. Last week several notable persistent slab avalanches were remotely triggered from skiers on adjacent slopes, particularly in the Selkirks and the northern tip of the Monashees. The most recent occurred in the Selkirks on Friday, where a size 2.5 slab on a south slope at 2200 m was remotely triggered from low angle trees.

Snowpack Summary

10 to 20 cm of low density snow sits above old wind slabs in the alpine, and in some isolated areas above small surface hoar (feathery crystals).A weak layer that formed during the dry spell in early December is now 80 to 120 cm deep. The layer is composed of weak facets, surface hoar, and a sun crust on steep south-facing slopes. This layer has been responsible for large persistent slab avalanches over the past two weeks, particularly on northeast facing slopes between 1900-2300 m and on steep south-facing slopes in the alpine.The lower snowpack is generally strong and settled, with a crust that formed in late October near the bottom of the snowpack.

Problems

Persistent Slabs

The likelihood of persistent slab avalanches is gradually decreasing, but triggering a widespread weak layer buried 80 to 120 cm beneath the surface would have major consequences. This problem will likely linger through the holidays.

Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.Minimize exposure to steep, planar, south-facing alpine slopesBe careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 27th, 2018 2:00PM