Avalanche Forecast

Issued: Jan 21st, 2022 4:00PM

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

Avalanche Canada zryan, Avalanche Canada

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Watch for changing conditions as a rise in temperature tests the upper snowpack. 

Summary

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

Friday Overnight: Cloudy, trace amounts of new snow. Strong to extreme southwest winds. Freezing level around 1200m.

Saturday: Partially cloudy, trace now snow. Moderate to extreme southwest winds. Freezing levels rising to 1500m.

Sunday: Mainly cloudy, up to 5 cm of new snow. Moderate to strong westerly winds. Freezing level around 500m.

Monday: Partially cloudy. Light to moderate northwest winds. Freezing level around 500m.  

Avalanche Summary

One large natural avalanche was reported on Friday near Smithers, the details can be viewed in this MIN report. The avalanche appears to have failed on a buried weak layer. This seems like an isolated event but we are keeping our eyes on a few weak layers in the upper snowpack with the warm temperatures and potential for some solar radiation tomorrow. 

Snowpack Summary

On Thursday, 10- 20 cm of new snow fell with strong southwest wind, which formed wind slabs in lee areas in wind-exposed terrain. Below around 1200 m, this snow landed on a hard melt-freeze crust.

Today, warming temperatures compounded by strong solar radiation may create loose wet avalanches on steep solar aspects, which have the potential to step down to buried weak layers and entrain a significant amount of mass. 

Two weak layers may exist. First is a layer of surface hoar that may be found around 30 cm deep. To date, this layer has produced avalanches in the centre and north of the region and not the south, though it has been found in the south. Next, a widespread layer of faceted grains is found around 30 to 60 cm deep, which formed during the cold spell in late December and early January. These layers have been most reactive in the central portion of the region.

In thin snowpack areas, the base of the snowpack is composed of weak faceted grains around various melt-freeze crusts, which are considered dormant at this time.

Terrain and Travel

  • Be alert to conditions that change with elevation and wind exposure.
  • Be careful as you transition into wind affected terrain.
  • Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs

Earlier in the week, 10-20 cm of new snow fell with strong southwest wind, which will continue into today. Expect to find reactive wind slabs in lee terrain features in wind-exposed terrain. It is possible you could also find storm slabs in steep terrain sheltered from the wind. These slabs may be particularly touchy where they sit on weak layer of surface hoar.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet

If the sun comes out today, solar radiation compounded by warm temperatures may have a destabilizing effect on the upper snowpack. Wet loose avalanches have the potential to step down to buried weak layers and entrain large amounts of mass.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Jan 22nd, 2022 4:00PM