Avalanche Forecast

Issued: Jan 20th, 2022 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada istorm, Avalanche Canada

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Warm temperatures may create tricky conditions this weekend. Although the region is not included in the avalanche warning, deeper layers in the snowpack may become active. Approach the mountains cautiously, with your eyes open, and maybe even expect surprises.  

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

Thursday is a powder day -- it's snowing!

THURSDAY NIGHT: Snowfall tapers overnight with only a few cm accumulating, strong wind from the west, treeline temperatures steady around -5 C with freezing level lowering from 1000 m down to 500 m.

FRIDAY: Cloudy with isolated flurries bringing trace amounts of snow, moderate wind from the west, treeline temperatures around -4 C to near zero. Freezing level rising and approaching 1500 m.

SATURDAY: A warm weather pattern is setting up. Mostly sunny, moderate wind from the northwest, a possible inversion developing which means cold in the valleys but above freezing temperatures between 1800 and 2000 m.

SUNDAY: The warm pattern continues with conditions similar to Saturday. There will likely be little overnight cooling near treeline elevations with a second day of above freezing temperatures as high as 2200 m.

Avalanche Summary

A widespread natural avalanche cycle occurred on Tuesday and Wednesday with size 2-3 storm and wind slabs observed in alpine terrain. Although we haven't received reports for Thursday at time of writing, a similar pattern of size 2 (or larger) avalanches is expected.

With forecast warm temperatures it's worth remembering that during last week's warm storm, a few size 2-2.5 deep persistent slab avalanche were observed near Blue River, as this corner of the region appears to have a similar lingering problem to the neighbouring North Columbia region.

Snowpack Summary

Expect 20 to 40 cm of recent storm snow by Friday morning. A few isolated surface hoar layers have been observed in the upper snowpack (top 100cm), as well as a thin breakable crust that extends up to 1800 m, but we have not seen avalanche activity on these layers.

The lower snowpack is strong and settled in most parts of the region, except the southernmost part of the region around Blue River where there is a deeply buried crust/facet layer that could be exhibiting similar behaviour to the deep persistent slab problem in the neighbouring North Columbia region. This layer is most prevalent at below treeline elevations and has been reactive to heavy triggers like smaller wind slab avalanches that step down to this layer.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Closely monitor how the new snow is bonding to the old surface.
  • Use small low consequence slopes to test the bond of the new snow.
  • Dial back your terrain choices if you are seeing more than 30 cm of new snow.

Problems

Storm Slabs

An icon showing Storm Slabs

New snow and wind will likely form unstable slabs in steep lee terrain features, especially along ridgetops.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 21st, 2022 4:00PM

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