Avalanche Forecast

Issued: Feb 17th, 2020 4:00PM

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

Parks Canada Grant Statham, Parks Canada

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Beautiful weather and good snow conditions will make for an excellent day on Tuesday. The sun is higher in late February, so be aware of the increased power of solar radiation on the snowpack. Ice climbers with long exposure times stick to the shade.

Summary

Weather Forecast

NW flow aloft will keep the temperatures relatively cool over the next few days, with overnight lows near -15 and daytime highs reaching -5. With the sun higher this time of year, be wary of the local heat that can develop in sheltered areas from solar radiation. No new snow and light winds are forecast for Tuesday.

Snowpack Summary

Continued settlement and cool temperatures are slowly stabilizing the recently formed windslabs, which could still be triggered in steep, loaded areas in the alpine. Suspect sun crust formation on steep S and SW facing terrain. Weak, facetted snow near the base of the snowpack persists in much of the range, producing isolated but large avalanches.

Avalanche Summary

No new avalanches were observed or reported on Monday, but Sunday saw many windslabs up to size 2 and a couple of very large (size 3.5) avalanches that ran to valley bottom.

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs

Recently formed windslabs are stabilizing but can still be triggered by people in steep leeward areas at treeline and in the alpine. Cornices have grown very large in recent weeks, so watch your exposure to them carefully.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Several large avalanches failing naturally on the basal facet/depth hoar have been observed in the past week. These are hard to predict, but are most likely in areas with a thin snowpack (~150cm) where the basal facets and depth hoar are prominent.

  • Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3.5

Valid until: Feb 18th, 2020 4:00PM

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