Avalanche Forecast

Issued: Apr 17th, 2014 8:00AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Wet and Persistent Slabs.

danyelle magnan, Parks Canada

Glacier.

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Summary

Weather Forecast

Today will be cloudy with flurries, possibly rain at lower elevations as freezing levels may rise to 1800m. This will taper off by Friday afternoon with temps dropping and the possibility of some sunshine in the afternoon. On Saturday, a warm and wet weather system will arrive with freezing levels rising to 2300m and strong SW winds.

Snowpack Summary

Temperatures barely dropped below zero overnight, giving a weak freeze. New snow will also soften the crust. The snowpack on solar aspects is warming to near isothermal levels, but it stills awaits a dramatic warming to lose its structural integrity.

Avalanche Summary

No new avalanches were observed in Glacier National Park yesterday. In neighboring areas, loose wet slides on a south aspect at 1600m triggered slabs 100cm deep and ran 300m. Also in neighboring areas, cornice failures have triggered avalanches to size 2.5 on north and east aspects in the alpine.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Loose Wet

Surface crusts will break down quickly due to a weak overnight freeze. With forecast rising freezing levels, watch for the possibility of rain showers at lower elevations which will further weaken the snowpack.

Start and finish early before the surface crusts melt.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Persistent weak layers deep in the snowpack are tough to trigger but another avalanche or a big cornice failure would wake them up. Rapid warming or rain could also trigger a very large avalanche.

Pay attention to overhead hazards like cornices.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 18th, 2014 8:00AM