Avalanche Forecast

Issued: Mar 20th, 2021 4:00PM

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

Avalanche Canada cgarritty, Avalanche Canada

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A bit of new snow has improved our skiing and riding conditions while giving forecast winds material to form new hazards. Keep an eye out for fresh wind slabs formed (or forming) on leeward slopes as you approach exposed terrain on Sunday.

Summary

Confidence

Moderate -

Weather Forecast

Saturday night: Mainly cloudy with scattered flurries bringing less than 5 cm of new snow. Light to moderate southwest winds, initially strong in the alpine.

Sunday: Cloudy with scattered flurries and up to 5 cm of new snow, continuing overnight. Light to moderate southwest winds, increasing over the day and becoming strong in the alpine. Alpine high temperatures around -5 with freezing levels to 1500 metres.

Monday: Cloudy with easing flurries bringing up to 5 cm of new snow. Light southwest winds. Alpine high temperatures around -5.

Tuesday: A mix of sun and cloud. Light southwest winds, becoming strong in the alpine overnight. Alpine high temperatures around -5.

Avalanche Summary

A bit more snow than was forecast was observed producing small natural dry loose releases from steep alpine terrain in the Fernie area on Saturday. With the addition of forecast light flurries, increasing winds will likely use this material to form small but reactive wind slabs in exposed terrain through the day on Sunday.

A large (size 2) glide slab occurred overnight and was observed on Friday morning on a lower elevation slope on Mt. Fernie. It may have been coaxed into action by overnight rainfall. This serves as a great reminder to avoid slopes with glide cracks on them at all times. They are inherently unstable and can release at any time.

Snowpack Summary

Up to 15 cm of new snow accumulated over wind affected surfaces at higher elevations over Friday night and Saturday and over a mix of refrozen or still wet snow at treeline and lower. Forecast light flurries will add a bit more dry snow to this mix at all but low elevations in the coming days.

Around 30 to 50 cm of snow sits above a layer of sugary faceted grains that were buried in mid-February. In some areas, there may be an old layer of feathery surface hoar or facets from late January down 50 to 80 cm deep. There have been no reported avalanches on either of these layers in the region in the last 10 days. Cool temperatures are expected to further decrease their likelihood of producing avalanches.

Terrain and Travel

  • Be alert to conditions that change with elevation.
  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.

Problems

Wind Slabs

An icon showing Wind Slabs

A bit more recent snow than expected has likely formed new wind slabs to manage in leeward terrain at upper elevations. Forecast light snow and high elevation winds should keep the possibility for this problem at top of mind as you reach exposed terrain.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Mar 21st, 2021 4:00PM