Avalanche Forecast

Archived

Dec 27th, 2024–Dec 28th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

South Columbia, Badshot-Battle, Central Selkirk, Goat, Gold, Kokanee, Retallack, Valhalla, Whatshan.

Choose mellow terrain that is sheltered from the wind.

Uncertainty about a persistent weak layer means that it's not time to venture into steep or consequential terrain.

Confidence

Moderate

Avalanche Summary

A large avalanche was remotely triggered on the early December layer (see this MIN). This shows that the early December layer may still linger, especially on north to east aspects around 2200 m. This layer may now be harder to trigger, but it could result in a very large, deadly avalanche.

Otherwise, numerous small natural and rider triggered avalanches were reported in the recent snow, especially in steep terrain.

Snowpack Summary

As moderate snowfall continues, expect to find 30 to 70 cm of settling snow in sheltered areas, and wind slabs on lee slopes below peaks and ridgelines. On sun affected slopes, the recent snow covers a melt freeze crust.

A concerning layer of facets, crusts, and in some places surface hoar is buried 60 to 110 cm deep. The distribution is variable throughout this region but it is most prevalent between 1700 to 2300 m.

Cornices are large and fragile from recent winds and mild temperatures.

Treeline snow depths range from 100 to 180 cm.

Weather Summary

Friday Night

Mostly cloudy with 3 to 5 cm of snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -6 °C.

Saturday

Cloudy with 5 to 15 cm of snow, possible hotspots of 20 cm or more. 20 to 35 km/h southwest ridgetop wind. Treeline temperatures -5 °C.

Sunday

Partly cloudy with 5 to 10 cm of snow, possible hotspots of 15 cm. 10 km/h north ridgetop wind. Treeline temperature -5 °C.

Monday

Mostly cloudy with up to 5 cm of snow. 5 to 15 km/h west ridgetop wind. Treeline temperature -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Be aware of the potential for large avalanches due to buried weak layers.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

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.