Avalanche Forecast

Archived

Jan 16th, 2024–Jan 17th, 2024

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Blue River, Premier, Clemina, Esplanade, North Monashee, North Selkirk.

Reactive storm slabs may build through the day and dry loose sluffing seen in steep terrain features.

Persistent slabs are best managed through conservative terrain selection.

Confidence

Moderate

Avalanche Summary

On Monday, the most notable avalanches happened just north of Revelstoke in the Selkirks. Two persistent slab avalanches were remotely triggered by skiers from up to 1 km away. They were reported to have failed on the early December surface hoar layer that is buried deeper in the snowpack. The avalanches occurred on east and south-facing slopes areas above 2100 m.

Fresh storm slabs may build on Wednesday and dry loose sluffing will likely continue from steep terrain.

Snowpack Summary

New snow will bury a variety of snow surfaces including unconsolidated faceted snow, surface hoar and firm wind-pressed snow in open terrain at treeline and above. Dry loose sluffing from steep terrain features is likely.

Down 50 -60 cm, a crust, facet and or surface hoar layer exists. This may become a problem once the snow above starts to stiffen and form a slab.

100+ cm down another surface hoar layer exists that was buried in early December. This seems to be of most concern above 2000 m where a robust crust doesn't exist above it.

The depth of the snowpack varies greatly throughout the region and weak basal facets are present at the base of the snowpack.

Weather Summary

Tuesday Night

New snow 5-10 cm. Ridgetop wind 15-25 km/h from the west. Treeline temperatures near -15 C.

Wednesday

Cloudy with 5-10 cm of snow. Ridgetop wind 20 km/h from the southeast and treeline temperatures near -11 C.

Thursday

Mix of sun and cloud. Ridgetop wind 10-20 km/h from the southeast. Treeline temperature -13 C.

Friday

New snow 5-10 cm. Ridgetop winds light from the southwest. Treeline temperatures near -3 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Be carefull with sluffing in steep terrain, especially above cliffs and terrain traps.

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.