Archived

Avalanche Forecast

Dec 25th, 2018–Dec 26th, 2018

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Columbia.

The persistent slab problem is best managed with patience and relatively conservative terrain choices. Read more in the new forecaster blog here.

Confidence

Moderate -

Weather Forecast

The BC weather will take a holiday break over the next couple of days as the wild storm cycle of recent weeks eases in the Pacific.CHRISTMAS NIGHT: Freezing level at valley bottom, light variable wind, no significant precipitation expected. BOXING DAY: Overcast, freezing level at valley bottom, light south/southwest wind, trace of snow possible. THURSDAY: Broken cloud cover, freezing level at valley bottom, light northerly wind, no significant precipitation expected. FRIDAY: Scattered cloud cover, freezing level at valley bottom, light northerly wind with potential for moderate gusts in the afternoon at upper elevation, trace of snow possible.

Avalanche Summary

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 is notable as that is below treeline. As the sun made an appearance a few small loose avalanches were also observed.The most recent 10-30 cm of low density snow was reactive to skiers on steep and convex features on Sunday. Otherwise, natural and human triggered activity has started to taper off.However, as recent as last Friday, large (size 2-3) persistent slab avalanches were occurring naturally. There have also been a few notable persistent slab avalanches remotely triggered from skiers on adjacent slopes. Most recently, last Wednesday a few large (size 2-2.5) avalanches on north-facing slopes were remotely triggered by skiers in the Selkirks.

Snowpack Summary

10-20 cm of low density snow sits above 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 50-100 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.

Avalanche 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.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.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 slopes

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3