Avalanche Forecast

Issued: Jan 27th, 2021 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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Wind slabs remain the primary concern. Sheltered terrain will offer the safest and best riding conditions.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

WEDNESDAY NIGHT: Clear skies, 20 km/h west wind, alpine temperature -20 C.

THURSDAY: Increasing clouds, 20 km/h west wind, alpine temperature -19 C.

FRIDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 20 to 40 km/h southeast wind, alpine temperature -15 C.

SATURDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 20 km/h south wind, alpine temperature -15 C.

Avalanche Summary

A few small wind slab avalanches were observed around White Pass on Tuesday in alpine terrain.

Looking forward, it may be possible for riders to trigger wind slab avalanches on all aspects due to sustained moderate wind and a shifting wind direction.

Snowpack Summary

In sheltered terrain, soft and consolidated snow may be found. In exposed terrain, a wind-affected snow surface prevails from recent northerly wind that is forecast to switch to the south. Wind affected snow varies from wind-pressed snow to hard and thick wind slabs, which generally hardens with elevation.

A buried weak layer of surface hoar may still be found around 90 cm deep. It was found around Log Cabin and also in Powder Valley (see here). Avalanche activity on this layer hasn't been reported since the first week of January and isn't expected to spike without a substantial snowfall or warming trend.

The lower snowpack is strong around White Pass but a thinner and weaker snowpack structure is expected inland, such as in the Wheaton Valley and the south Klondike.

Terrain and Travel

  • Watch for areas of hard wind slab on alpine features.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs

The wind was recently blowing from the north but is forecast to shift to the south. Wind slabs therefore may be found on all aspects in wind-exposed terrain. Assess for wind effect as you travel and use caution where you find a slabby snow surface.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 29th, 2021 4:00PM