Avalanche Forecast

Issued: Dec 28th, 2020 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Triggering wind slab avalanches is likely on open slopes with the arrival of new snow and strong wind on Tuesday.

Summary

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

A front will bring active weather between Monday night and Wednesday morning.

MONDAY NIGHT: 5-10 cm of snow, 40-60 km/h south wind, temperatures around -7 C.

TUESDAY: Frontal intensity peaks in the morning then eases in the afternoon, another 5 cm of snow throughout the day, 50-70 km/h south wind, temperatures around -7 C.

WEDNESDAY: Mostly cloudy, light wind with moderate gusts, temperature around -8 C. 

THURSDAY: Light flurries with trace amounts of snow, light wind, temperatures around -12 C.

Avalanche Summary

No notable avalanche activity was reported over the weekend as older wind slabs appear to be mostly unreactive. Looking ahead the frontal system crossing the region on Tuesday will form new wind slabs that will likely be reactive on leeward terrain features.

Snowpack Summary

A frontal system will bring a moderate amount of snow with strong south wind on Tuesday. This will result in extensive wind slab formation in open terrain, especially on north-facing leeward terrain. The new snow will bury older wind slabs, which can be found on all aspects but have been unreactive over the weekend. A buried crust can be found 60-100 cm below the surface, but reports suggest the snow is well-bonded to this crust. The lower snowpack is strong around White Pass, however there is potential for a weaker snowpack structure in inland areas such as the Wheaton Valley. 

Terrain and Travel

  • Sheltered low elevation terrain will likely offer the best and safest riding today.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid terrain traps where the consequence of any avalanche could be serious.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow and wind will form reactive wind slabs on leeward terrain such as below ridges and the sides of gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 30th, 2020 4:00PM