Avalanche Canada shorton, Avalanche Canada

South 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 Wind Slabs and Persistent Slabs.

Watch for changes in the surface snow as you travel through terrain and approach steep and open slopes cautiously.

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: Scattered flurries with 5-15 cm of low density snow, light to moderate wind from the southwest, alpine temperatures drop to -12 C.

SUNDAY: Scattered flurries with 5-10 cm of low density snow, light wind from the south, alpine high temperatures around -10 C.

MONDAY: Flurries in the morning with 5-10 of low density snow then sunny in the afternoon, light wind from the west, alpine high temperatures around -15 C.

TUESDAY: Mix of sun and cloud with isolated flurries and up to 5 cm of new snow, light wind from the west, alpine high temperatures around -15 C.

Avalanche Summary

Recent accumulations of low density snow resulted in several small wind slab and dry loose avalanches on Friday. A storm earlier in the week resulted in several large avalanches (size 2-3). These avalanches released on both a 100-150 cm deep surface hoar layer and in a few notable cases on deep persistent weak layers (on west, north, and northeast aspects in the alpine). Looking forward these deep layers will become less likely to trigger, but careful snowpack evaluation is still recommended.

Snowpack Summary

Low density snow continues to accumulate, with 30-50 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 thin crust exists in many areas 50-100 cm below the surface, and beneath that is a layer of surface hoar has been the culprit in recent large avalanches. This layer is roughly 80-120 cm deep in the Selkirks and 120-150 cm deep in the Monashees. A facet/crust layer from late November lingers near the bottom of the snowpack and has shown reactivity in isolated shallow snowpack areas.

Terrain and Travel

  • Approach steep, open and/or sparsely treed slopes cautiously.
  • Be careful as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

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:

North, North East, East, South East, South, North West.

Elevations:

Alpine, Treeline.

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Unlikely-Possible

Expected Size

2 - 3

A surface hoar layer that formed in late December is now buried 80 to 150 cm below the surface. At this depth it becomes more difficult to trigger, but steep open slopes should still be approached with caution.

Aspects:

All aspects.

Elevations:

All elevations.

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