Avalanche Forecast

Issued: Feb 12th, 2020 5:00PM

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

Avalanche Canada MBender, Avalanche Canada

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Flurries are forecast to bring 5-10 cm of new snow on Thursday. Expect avalanche danger to increase through the day as the snow accumulates and the wind redistributes the snow into reactive slabs.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday Night: Cloudy with clear breaks. Light west wind. Alpine high temperatures around -6.

Thursday: Flurries, accumulation 5-10 cm. Light to moderate southwest wind. Alpine high temperatures around -7. Freezing level 900 m

Friday: Scattered flurries. Moderate west and southwest wind. Alpine high temperatures around -8. Freezing level 600 m

Saturday: Flurries. Moderate west wind. Alpine high temperatures around -9. Freezing level 700 m

Avalanche Summary

On Monday and Tuesday there were reports of several wind slabs, storm slabs and cornices running naturally size 1.5 to 2 on south, east and north aspects in the alpine. On Tuesday there were a few thin size 1-1.5 skier rider triggered avalanches.

On Monday there was also a report of a skier triggered size 2 wind slab on a southeast aspect at 2300 m. This was described as an old wind slab which was obscured by 20 cm of new snow.

Snowpack Summary

30-60 cm of snow falling over the last week overlies older wind-affected snow at high elevations as well as a widespread melt-freeze or rain crust with an upper extent that varies from 1900 metres in some areas to mountaintop in others. This snow has been redistributed by moderate to strong winds blowing from a variety of directions. The depth of new snow diminishes considerably at lower elevations. 

The mid and lower snowpack are generally well settled and strong, but contain two deeper weak layers that we have been tracking since the early part of the season. The late December surface hoar layer, buried 100 to 180 cm deep, is now suspected to be dormant.

A facet/crust layer from November exists near the ground in the highest elevations of the region. It remains a limited concern that is likely only able to be triggered with a large load, in high elevation, thin snowpack areas of the Selkirks and the southern half of the region.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Wind slabs are most reactive during their formation.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent light snowfall combined with elevated and shifting winds have built wind slabs on a variety of aspects. 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 13th, 2020 5:00PM