Avalanche Canada shorton, Avalanche Canada

North Columbia Avalanche Forecast

Jan 10th, 2020 5:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Persistent Slabs.

Watch for areas where the new snow feels stiff or slabby and remain cautious of open slopes and convex rolls.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

FRIDAY NIGHT: Cloudy with isolated flurries and 5-10 cm of snow, light wind from the southwest, alpine temperatures drop to -14 C.

SATURDAY: Cloudy with scattered flurries and 5-10 cm of snow, light wind from the west, alpine high temperatures around -10 C.

SUNDAY: Scattered flurries with 5-10 cm of snow, light wind, alpine high temperatures around -12 C.

MONDAY: Mostly sunny, light wind from the southwest, alpine high temperatures around -20 C.

Avalanche Summary

Avalanche activity is likely on the decline as only moderate accumulations of low density snow are expected over the weekend, although there is uncertainty about whether wind could be forming fresh slabs at higher elevations.

Wednesday's storm resulted in widespread avalanche activity with numerous large and very large avalanches (size 2-3). Both storm slab and persistent slab avalanches were reported across aspects and elevations during this period. Persistent slab avalanches were breaking a meter deep, and one of them was remote-triggered. By Thursday the layer was less reactive with only explosive triggered avalanches reported. Preliminary reports from Friday suggest the most recent low density snow was sluffing and producing thin soft slabs.

Snowpack Summary

Low density snow continues to accumulate. Most areas likely have 20-30 cm of soft snow, but stiffer and reactive slabs could be forming in terrain affected by the wind. Recent storms have buried two layers of surface hoar from late December now down 80-140 cm deep. These layers produced large to very large avalanches across all aspects and elevations over the past week.

Terrain and Travel

  • Sheltered slopes at lower elevations will offer the best riding.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely

Expected Size

1 - 2

Low density snow may be blown into unstable slabs on lee features at and above treeline, especially near ridgetops.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Possible

Expected Size

2 - 3.5

Two layers of surface hoar from late December are now buried 80-140 cm deep. Large avalanches breaking on these layers reported Wednesday give clear evidence that these persistent weak layers are still a concern.

Aspects:

All aspects.

Elevations:

Treeline, Below Treeline.

Valid until: Jan 11th, 2020 5:00PM