Avalanche Forecast

Issued: Jan 18th, 2022 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Avalanches are possible at upper elevations where wind slabs are forming.

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

TUESDAY NIGHT: Clear skies, light wind from the west, treeline temperatures around -12 C.

WEDNESDAY: Clear skies in the morning with increasing cloud in the afternoon, light to moderate wind from the southwest, treeline temperatures warming to -7 C.

THURSDAY: Moderate snowfall with 5-15 cm of new snow, strong wind from the southwest, treeline temperatures warming to -4 C with freezing level reaching 1000 m.

FRIDAY: Mix of sun and cloud, moderate wind from the northwest, treeline temperatures around -4 C with freezing level reaching 1100 m.

Avalanche Summary

Poor visibility limited observations on Monday, however there was evidence of natural storm slab avalanches (size 2) above 1000 m and some wet loose avalanches below 1600 m.

On Sunday, some minor sluffing was observed with skier traffic in steep terrain. On Saturday, size 1 wind slabs were reactive to ski cuts. A couple of large persistent slab avalanches size 2-2.5 were observed near Blue River, suspected to have run naturally during the warm storm Thursday, during a natural avalanche cycle with storm slabs up to size 3.

Snowpack Summary

20-40 cm of new snow sits atop an upper snowpack consisting of warm, well settled snow containing a couple of layers of surface hoar in sheltered areas, and/or a thin breakable crusts observed as high as 1800 m.

A layer of facets from early January may be found down 40-80 cm but has not been reactive recently.

South of Blue River, the early December crust/facet interface is now typically down 80-150 cm, but as deep as 200 cm in wind loaded terrain. It consists of faceted grains above a decomposing crust formed by the Atmospheric River rain event at the end of November. Natural avalanches ran on this layer as recently as Thursday during the warm storm. Heavy triggers like natural cornice falls and wind slab avalanches may still have potential to step down to this layer resulting in very large avalanches. This snowpack feature is not found north of Valemount.

Terrain and Travel

  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Closely monitor how the new snow is bonding to the old surface.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent snow is stabilizing quickly in most areas, however cold windy weather will likely leave unstable wind slabs at upper elevations, especially along ridgetops.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 19th, 2022 4:00PM

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