Avalanche Forecast

Archived

Dec 30th, 2023–Dec 31st, 2023

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Inland, Howson, Kispiox, Microwave-Sinclair, North Bulkley, South Bulkley, South Bulkley, South Bulkley, Telkwa.

Persistent slab avalanches remain possible to trigger. Watch for signs of instability such as whumpfing.

Confidence

High

Avalanche Summary

On Thursday a large (size 2.5) naturally triggered wind slab avalanche was reported near Ashman.

Whumpfing has been experienced by backcountry users in the Babines, Grizzly Plateau, and Hudson Bay Mountain recently. The whumpfing has been occurring mainly due to the surface hoar layers described in the snowpack summary.

Snowpack Summary

Light amounts of recent new snow has been redistributed by primarily southerly winds. Southerly faces in the alpine are scoured down to the ground or an early-season crust. In most areas, two or more preserved surface hoar layers can be found buried between 35 cm and 80 cm deep. They appear to be most prominent at treeline and below but have been observed in some alpine locations as well.Snowpack depths at treeline are variable across the region with generally deeper amounts (~150cm) in the western part and shallower (~80cm) in the eastern part.The snow surface is likely moist or crusty up to treeline. Below 1100 m there is very little snow.

Weather Summary

Saturday Night

Cloudy with 2-4 cm of snow, southwest wind 20-30 km/h, freezing level 1000m and treeline temperature -1 °C.

Sunday

Mostly cloudy with sunny breaks, westerly wind 10-25 km/h, high of -5 °C at treeline.

Monday

Mainly cloudy with 1-3 cm new snow, south and southwest wind 20-40 km/h, high of -4 °C at treeline.

Tuesday

Mostly cloudy with flurries, southeast wind 10-20 km/h, high of -3 °C at treeline.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

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.

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.