Avalanche Forecast

Archived

Jan 6th, 2023–Jan 7th, 2023

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 possible, human triggered probable.

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, human triggered possible.

Regions

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

The song remains the same.

Conservative terrain selection is the best management for tricky persistent layers. Be wary of rocky start zones where the snowpack varies from thick to to thin. Weak layers are more easily triggered here.

Check out the new Forecasters' Blog for more details on managing our challenging snowpack.

Confidence

Moderate

Avalanche Summary

Persistent slabs and deep persistent slabs continue to be reported throughout the region, naturally and human triggered to size 3. Avalanches are failing on the weak layers described in the Snowpack Summary, from 70 cm and up to 200 cm deep in wind affected terrain. Activity has been reported on all aspects, mostly between 1800 and 2500 m elevation. Recent MIN reports showcase conditions well: check out Joss Mountain, & North McCrea Mt MINS.

These avalanches continue to indicate that these buried weak layers remain reactive, and capable of producing large consequential avalanches. Conditions will continue to be tricky for a while - many of these human-triggered avalanches were a surprise to the individuals triggering them.

Small slabs in wind loaded features have also been triggered by riders, which have the potential of stepping down to the deeper weak layers.

Snowpack Summary

30 to 50 cm of soft snow is on the snow surface in areas sheltered from the wind. Wind slabs are forming in lee terrain features from strong southerly wind in wind-exposed terrain. New wind slabs may sit over a layer of surface hoar and/or crust.

The upper snowpack is generally settled and well-bonded, however buried weak layers in the mid and lower snowpack continue to be a concern, with large and surprising (remote or accidentally triggered) avalanche activity reported throughout the last week.

A weak layer of crust, facets and/or surface hoar buried just before Christmas is buried 40 to 70 cm deep. The lower snowpack is generally weak and facetted with a weak layer of large facets from mid-November found near the ground.

Snowpack depths are roughly 150 to 200 cm at treeline. This year's snowpack is weaker than usual, as described in our Forecasters' blog.

Weather Summary

Friday Night

Cloudy with possible flurries. Moderate southwest wind. Freezing level drop to 500 m.

Saturday

Cloudy with light snowfall, accumulation 2 to 5 cm. Moderate southerly wind. Alpine high of -3 °C. Freezing levels 800-1000 m.

Sunday

Cloudy with light snowfall, accumulations up to 2 cm. Moderate southerly wind. Alpine high of -3 °C. Freezing levels 800-1000 m.

Monday

Cloudy with light snowfall, accumulations up to 5 cm. Moderate southerly wind. Alpine high of -3 °C. Freezing levels 800-1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be mindful that deep instabilities are still present and have produced recent large avalanches.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

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.