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Avalanche Forecast

Jan 15th, 2021–Jan 16th, 2021
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

Wind and flurries are expected to continue through the weekend, likely forming fresh and reactive wind slabs at upper elevations. Look for low-angle slopes in sheltered areas for the best snow, and the safest riding.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

FRIDAY NIGHT - Mainly cloudy with a few flurries / southwest wind, 50-70 km/h / alpine low temperature near -7 

SATURDAY - Flurries, 5-10 cm / southeast wind, 60-80 km/h, gusting to 100 km/h / alpine high temperature near -4 / freezing level 1000 m

SUNDAY - Cloudy with a few flurries, 3-5 cm / southwest wind, 40-60 km/h / alpine high temperature near -3 / freezing level 1200 m

MONDAY - Mainly cloudy / southwest wind, 40-60 km/h / alpine high temperature near -1 / freezing level 1500 m

Avalanche Summary

Wind slabs will likely continue to be reactive on Saturday.

There were a few reports of natural avalanches being heard on Thursday in the southwest of the region, but reports of poor visibility in several areas limited observations. 

There was a report of a natural avalanche cycle up to size 2 from wind loaded terrain in the south of the region on Tuesday.

There were a few explosives triggered size 2 persistent slab avalanches reported near the southern boundary of the region on Sunday.

Last Saturday, explosive control work near Ningunsaw (just outside the region) produced several wind slabs to size 2.5 and one size 3 deep persistent slab failing on weak facets near the base of the snowpack. Another reminder of the "low probability; high consequence" scenario that persistent slab problems often create.

Snowpack Summary

5-10 cm of new snow is expected in the region on Saturday, though areas in the west, near the boundary with the Northwest Coastal region may see as much as 20 cm. Fresh wind slabs will likely be forming in many areas, including at lower elevations. 

20-50 cm of recent storm snow may sit on a weak layer of surface hoar that was recently buried at treeline and below treeline.

In the south of the region, another weak layer of surface hoar that was buried around the New Year has been reported down 50-70 cm in sheltered areas.

The lower snowpack has two crusts with potentially weak, faceted snow around them. Reports from the Smithers area suggest the upper crust is 70-140 cm below the surface and has shown signs of being possible to trigger from shallow areas. The deeper crust is near the bottom of the snowpack and is most likely to trigger from steep, rocky slopes, with a shallow or thin to thick snowpack.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Keep your guard up at lower elevations. Wind slab formation has been extensive.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.

Avalanche Problems

Wind Slabs

Fresh wind slabs are likely forming with some new snow and strong to extreme winds. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

Triggering large avalanches on weaknesses in the lower snowpack remains a possibility. In some areas the concern is weak snow around crusts 70-140 cm deep, while in others it is weak snow near the bottom of the snowpack. Human triggering of these layers are most likely in steep, rocky slopes with a shallow or thin to thick snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3