Avalanche Forecast

Issued: Feb 14th, 2020 5:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Triggering fresh wind slab avalanches will continue to be a concern with light flurries and gusty wind expected the next few days.

Summary

Confidence

Moderate - Uncertainty is due to the complexity of the snowpack’s structure.

Weather Forecast

FRIDAY NIGHT: Cloudy with light flurries, strong wind from the southwest, alpine temperatures drop to -10 C.

SATURDAY: Cloudy with isolated flurries and up to 5 cm of new snow, strong wind from the west, alpine high temperatures around -6 C.

SUNDAY: Mix of sun and cloud, moderate wind from the west, alpine high temperatures around -8 C.

MONDAY: Mostly cloudy with isolated flurries, light wind from the northwest, alpine high temperatures around -8 C.

Avalanche Summary

Avalanche activity over the past week has primarily been wind slab avalanches. This includes size 1.5-2 naturally-triggered avalanches on a variety of aspects and size 1-1.5 human-triggered avalanches on primarily north aspects. New snow has likely refreshed the wind slab problem.

An isolated large (size 2.5) deep persistent slab avalanche was reported last Saturday. It was 130 cm thick and was remotely triggered (from a distance) in a shallow area on an east aspect at 2300 m. A decreasing trend in the number of persistent slab avalanches over the past few weeks suggests these large avalanches are unlikely to trigger under the current conditions.

Snowpack Summary

20-50 cm of low density snow has fallen over the past week and has been blown into isolated wind slabs at upper elevations. This snow sits above a rain crust that extends up to about 1700 m. The mid and lower snowpack are generally well settled, however an aging weak layer of surface hoar 70 to 150 cm below the surface from late December was a recent concern in southern parts of the region on slopes between 1700-2400 m (above the crust elevation and below the most wind-affected elevations). A facet/crust layer from November may be found near the ground in shallower snowpack areas and has been the suspected cause of sporadic very large avalanches releasing the past two weeks. Both of these weak layers have trended towards being unreactive under the current conditions.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Use caution when approaching steep and rocky terrian.

Problems

Wind Slabs

An icon showing Wind Slabs

Accumulations of new snow over the past week have formed reactive slabs in steep wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 15th, 2020 5:00PM