Avalanche Forecast

Issued: Feb 4th, 2023 4:00PM

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

Avalanche Canada CJ, Avalanche Canada

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Wind and cornice triggered slab avalanches in the alpine have occurred daily during the past week, occasionally stepping down to deeper layers in the snowpack.

Use caution in steep lee-loaded terrain, and minimize your exposure to overhead hazards in areas where wind loading is occurring above you.

Summary

Confidence

Moderate

Avalanche Summary

Size 1-2 natural, skier and explosive triggered wind slabs have been observed every day for the past several days. Occasionally these have stepped down to deeper layers in the snowpack.

Forecasters in Yoho on Saturday were able to trigger small wind slabs on steep rolls and had shooting cracks while travelling in wind effected areas.

Snowpack Summary

5-8 cm of new snow on Saturday. Continuous moderate to strong west winds have formed new wind slabs with extensive wind effect at alpine and treeline elevations. The upper snowpack has several crusts and weak interfaces from January down 15-50 cm. The Nov 16 deep persistent facet layer is down 40-110 cm and continues to produce sudden test results. The mid and lower pack is weak in eastern regions and more supportive in western areas and along the divide.

Weather Summary

Scattered flurries on Sunday morning before a cold front moves through the region bringing 2-5 cm of snow to areas along the divide, with flurries to the East. Winds will be westerly in the moderate-strong range. Alpine high temperatures will range from 0 to -5°C with freezing levels between 1400-1600 m.

More details can be found in the Mountain Weather Forecast

Terrain and Travel Advice

  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • In times of uncertainty conservative terrain choices are our best defense.

Problems

Wind Slabs

An icon showing Wind Slabs

A bit of new snow and continued moderate to strong W winds have formed wind slabs at alpine and treeline elevations. These can be triggered by skiers and climbers in steep lee loaded areas. Natural activity has also occured in each of the past few days from wind loading and cornice failures. If triggered, there is potential for these wind slabs to step down to deeper layers in the snowpack resulting in larger avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The lower snowpack is comprised of weak facets and depth hoar with the upper snowpack forming a 40 to 110 cm thick slab above the weakness. Natural and human triggering on this layer remains a concern.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3.5

Valid until: Feb 5th, 2023 4:00PM