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Avalanche Forecast

Archived

Dec 25th, 2018–Dec 26th, 2018

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

North Columbia.

We're into a week of stable weather, but a persistent slab problem still warrants 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 southerly wind, no significant precipitation expected. BOXING DAY: Overcast, freezing level at valley bottom, light southerly 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 southerly wind with potential for moderate gusts late in the day at upper elevation, trace of snow possible.

Avalanche Summary

On Monday riders triggered 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. Otherwise, natural and human triggered activity has started to tapered off.Over the past week, several notable persistent slab avalanches have been 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

10-20 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 80-120 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

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.