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Avalanche Forecast

Jan 7th, 2021–Jan 8th, 2021
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
1: Low
The avalanche danger rating below treeline will be low
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
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Coast Inland.

 Heightened avalanche conditions exist on wind loaded slopes. In the north of the region, the likelihood of triggering deeply buried weak weak layers is reducing, however the consequences of doing so are still high. 

Confidence

Moderate - Recent weather patterns have resulted in a high degree of snowpack variability within the region.

Weather Forecast

Thursday Night: Mainly cloudy with clear periods, moderate southeast wind, alpine high -7, freezing level at valley bottom.

Friday: Scattered flurries, 1 to 5 cm, moderate to strong southwest wind, alpine high -5, freezing level 700 m.

Saturday: Mainly cloudy with sunny breaks, light to moderate south wind, alpine high -4, freezing level 800 m.

Sunday: Mainly cloudy with flurries, moderate south wind, alpine high -3, freezing level 1000 m.

Avalanche Summary

Reports from Wednesday include a human triggered size 2 storm slab avalanche at 2000 m on a north aspect in the Duffey Lake area. As well a few natural size 1-1.5 naturally triggered windslabs in the alpine. On Tuesday there was a size 2 persistent slab avalanche reported on Joffre Shoulder. See this MIN report for more details.

 

Persistent slab avalanche activity has tapered significantly since early last week, but persistent slabs size 2-2.5 were still triggerable by explosives on the weekend.

Snowpack Summary

Over 70 cm of recent snow in the past week has seen extensive wind affect at upper elevations, with scoured windward aspects, wind slabs in lee features and growing cornices at ridgetop. In sheltered areas below treeline, recent snow may be sitting on surface hoar. 

A melt-freeze crust from early December is found around 80 to 180 cm deep in the snowpack. This crust may have surface hoar or sugary faceted grains sitting above it. This persistent weak layer is most prevalent in the north (e.g., Duffey Lake, Hurley) and found to a lesser extent in the south of the region.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Be aware of the potential for large avalanches due to the presence of a deep persistent slab.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Avalanche Problems

Wind Slabs

New snow combined with primarily southwest wind on Tuesday night has created reactive wind slabs.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

A couple of problematic layers may be found around 80 to 180 cm deep primarily in the north of the region (e.g. Duffey, Hurley), including weak layers of surface hoar and faceted grains above a hard melt-freeze crust. Although the likelihood of triggering is reducing, the consequences of doing so would be high.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 3