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

South 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 -

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, a ridge of high pressure will likely take us into the New Year.WEDNESDAY NIGHT: Freezing level at valley bottom, light northerly 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 to strong west/northwest wind in the alpine, a few centimeters of snow possible during the day. 2 to 8 cm of snow Friday night.SATURDAY: Overcast, freezing level beginning at valley bottom, rising to around 1500 m by sunset. Strong southwest wind, 8 to 15 cm of snow.

Avalanche Summary

No new avalanche activity to report from Tuesday. On Monday a few old size 2 natural avalanches were observed on south facing features between 1600 and 2300 m. The avalanche at 1600 m was notable as it was below treeline. As the sun made an appearance a few small loose avalanches were also observed.As recent as last Friday, large (size 2-3) persistent slab avalanches were occurring naturally.

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 50 to 100 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 north and east 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 50 to 100 cm beneath the surface would have major consequences. This problem will likely linger through the holidays.

Minimize exposure to steep, planar, south-facing alpine slopesUse caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.Be 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