Avalanche Forecast

Archived

Dec 21st, 2023–Dec 22nd, 2023

Alpine

Natural avalanches possible, human triggered probable.

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Cariboos, North Columbia, Blue River, Clearwater, McBride, Premier, Quesnel, Clemina, Jordan, North Monashee, North Selkirk, Renshaw, Robson.

Assess conditions throughout the day, watch for signs of instability.

Storm slabs could increase in size and the additional load will increase the chance of persistent slab avalanches.

Confidence

Moderate

Avalanche Summary

Explosive control and ski cutting have produced wet loose and storm slab avalanches up to size 2. These avalanches have been at treeline and generally failing on one of the shallower surface hoar layers.

Large human and remotely triggered avalanches continue to occur in neighboring regions. These avalanches are generally occurring at or above treeline and are failing on the surface hoar layer from early December.

Snowpack Summary

o 40 cm of recent snow has buried a layer of surface hoar in wind-sheltered terrain. A crust from the early December rain event is buried by roughly 50 cm of snow.

A problematic surface hoar layer is now roughly 60 to 100 cm below the surface.

The lower snowpack is generally facetted with a hard crust found just above the ground. The snowpack remains unseasonably shallow, with average treeline snow depths around 80 to 120 cm.

Weather Summary

Thursday Night

Mostly cloudy with a few centimeters of new snow expected, south alpine wind 15 to 40 km/h, freezing level between 1000 and 1500 m.

Friday

Cloudy with 10 to 20 cm of new snow expected, south alpine wind 30 to 50 km/h, freezing level around 1500 m.

Saturday

A mix of sun and cloud with no new snow expected, west alpine wind 20 to 40 km/h, freezing level at valley bottom.

Sunday

A mix of sun and cloud with no new snow expected, southwest alpine wind 10 to 25 km/h, treeline temperature -8°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Uncertainty is best managed through conservative terrain choices at this time.
Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
Wind slabs are most reactive during their formation.
Avoid areas where the snow feels stiff and/or slabby.

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.