Avalanche Forecast

Archived

Jan 5th, 2022–Jan 6th, 2022

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, 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.

Regions

Northwest Coastal.

The upper snowpack is heavily wind effected. Seek out sheltered terrain at treeline and below where you can avoid wind slabs and find good riding.

Remember that days are short and temperatures are cold! Keep your objectives conservative and close to home.

Confidence

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack. Uncertainty is due to the limited number of field observations.

Weather Forecast

Wednesday Overnight: Mainly cloudy, light to moderate southeast winds. Alpine temperatures around -25 C.

Thursday: Partially cloudy with light flurries. Alpine temperatures rising to -20 C. Light easterly winds.

Friday: Mainly cloudy with light flurries. Northwest winds increasing strong to extreme in the afternoon. Alpine temperatures around -15 C.

Saturday: Snowing through out the day, 2-10 cm of accumulation. Alpine temperatures rising to around -15 C. Moderate to strong southwest winds.

Avalanche Summary

On Wednesday, a natural size two wind slab was observed in the alpine on a north aspect in the Kitimat ranges.

On Tuesday, operators north of Terrace reported two size one wind slab avalanches; one skier-triggered, and one natural. These avalanches occurred on slopes that had been recently loaded by northerly outflow winds.

On Monday, numerous natural and explosive triggered wind slab avalanches up to size 3 were reported at treeline and above, on a variety of aspects.

If you are out in the mountains, let us know what you see by filling out a Mountain Information Network report! ?

Snowpack Summary

Southeasterly winds may continue to form reactive wind slabs on lee features at all elevations.

Freshly formed wind slabs are most likely to be found on north and westerly aspects, but older wind slabs may be found on all aspects. Recently formed wind slabs may remain reactive to human triggers for longer than is typical due to the weak facets (sugary snow) they are sitting on.

The early December rain crust is up to 10cm thick, down 80-150cm in the snowpack, and exists to an average of 1400m in elevation. Up to 2mm facets have been reported above this crust, and it is producing hard but sudden planar results in snowpack tests in areas north of Terrace.

Avalanches on this weak layer can be best managed by avoiding likely trigger spots such as steep, rocky slopes, with a shallow or thin to thick snowpack.

Terrain and Travel

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Be aware of highly variable recent wind loading patterns.
The best and safest riding will be on slopes that have soft snow without any slab properties.
Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
Keep your guard up at lower elevations. Wind slab formation has been extensive.

Problems

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.