Avalanche Forecast

Archived

Dec 27th, 2022–Dec 28th, 2022

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

North Columbia, South Columbia, Blue River, Clearwater, Premier, Clemina, Esplanade, Jordan, North Monashee, North Selkirk, West Purcell, Badshot-Battle, Central Selkirk, Goat, Gold, Whatshan.

Warm temperatures and continued snowfall will keep the avalanche hazard elevated.

Slabs are now primed to release and smaller avalanches may trigger buried weak layers producing large avalanches. If you start to see natural avalanche activity consider a heightened danger rating.

It's a good day to play it conservatively.

Confidence

Moderate

Avalanche Summary

Snow that has been falling since Friday and a warming trend that started on Monday continues conditions for avalanche activity.

The majority of these avalanches have occurred naturally from the storm snow. There have been a number of small and large avalanches that people have triggered accidentally. Again these have occurred from storm slabs but several large avalanches that were accidentally human-triggered and slid on buried weak layers.

Slab reactivity is expected to increase in the storm snow as well as the multiple buried weak layers buried beneath.

Snowpack Summary

Warm temperatures and moist snow have promoted slab properties in the top layer of the snowpack. Another 10 to 15 cm will add to this process. Before the warming trend that started on Monday, the top 50 to 75 cm of the snowpack was fairly unconsolidated. Strong southwest winds will have redistributed much of this snow at higher elevations, where it may be cooler, into fresh wind slabs. Slabs that are formed may not bond well to older surfaces.

There are up to three weak layers created earlier in December. Some of these may not exist in all areas of our region. The November weak layer, which will continue to be a concern in this warm-up, can be found anywhere between 75 and 125 cm down. The bottom of the snowpack is generally weak and faceted.

With a snowpack such as this, it is important to keep a heads up and know that very small avalanches can quickly become very large. Check out our forecaster blog to learn about how to manage persistent slab problems.

Weather Summary

Tuesday Night

Cloudy, 4 to 10 cm accumulation, 20 km/h southwest wind, treeline temperatures -5 to -2 °C.

Wednesday

Mostly cloudy, up to 6 cm accumulation, 10 to 20 km/h southwest wind, treeline temperatures -5 °C.

Thursday

Mostly cloudy with sunny periods in some areas, 0 to 5 cm accumulation, 20 to 30 km/h southeast wind, treeline temperatures -10 to -5 °C.

Friday

Cloudy, up to 6 cm accumulation, 25 km/h south wind, treeline temperatures -10 to -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Good day to make conservative terrain choices.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Be carefull around freshly wind loaded features.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.