Avalanche Canada shorton, Avalanche Canada

North Columbia Avalanche Forecast

Jan 11th, 2020 5:00PM

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

SATURDAY NIGHT: Mostly cloudy with light isolated flurries, light to moderate wind from the west, alpine temperatures drop to -15 C.

SUNDAY: Scattered flurries with 5-15 cm of low density snow, light wind, alpine high temperatures around -12 C.

MONDAY: Mix of sun and cloud, light wind from the west, alpine high temperatures around -20 C.

TUESDAY: Mostly sunny, light wind from the west, alpine high temperatures around -22 C.

Avalanche Summary

Recent accumulations of low density snow resulted in several small (size 1) slab and dry loose avalanches on Friday. There were also a few reports of human triggered persistent slab avalanches that released on a 100 cm deep surface hoar layer on north and east aspects (including this MIN report from Clemina). There have been numerous reports of similar persistent slab avalanches over the past week, suggesting the buried surface hoar layer remains reactive to human triggering in the North Columbias, especially between 1200 and 2100 m.

Snowpack Summary

Low density snow continues to accumulate, with 20-40 cm of fresh light snow on the surface. Cold temperatures and light wind should preserve this snow with the exception of some higher elevation terrain where isolated wind slabs could exist. A layer of surface hoar is now buried 80-120 cm below the surface and continues to be a concern across the region. A facet/crust layer from late November lingers near the bottom of the snowpack and has occasionally been reactive in isolated shallow snowpack areas.

Terrain and Travel

  • Approach steep, open and/or sparsely treed slopes cautiously.
  • Be especially cautious as you transition into wind affected terrain.

Problems

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Possible

Expected Size

2 - 2.5

A weak layer of surface hoar is buried 80-120 cm deep and has produced numerous human triggered avalanches over the past week. Steep open slopes at and below treeline should be approached cautiously.

Aspects:

All aspects.

Elevations:

Treeline, Below Treeline.

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible-Likely

Expected Size

1 - 2

Monitor changes in the most recent low density snow. It may be blown into unstable slabs in wind affected terrain or run as small dry loose avalanches in steep terrain.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Valid until: Jan 12th, 2020 5:00PM