Avalanche Forecast

Issued: Jan 11th, 2014 9:33AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada slemieux, Avalanche Canada

Strong winds from the West are expected to keep loading lee slopes tomorrow and possibly trigger large avalanches.

Summary

Confidence

Good

Weather Forecast

Tonight and Sunday: The tail of the system exiting is expected to leave more precipitation tonight. Light to moderate amounts are forecasted for tonight (around 15 mm in water equivalent) and none during the day tomorrow with strong winds from the W. Freezing levels should fall to valley bottom tonight. There could be some clearings in the morning tomorrow. Monday: Another warm front is pushing in bringing light amounts of precipitation during the night between Sunday and Monday, strong Westerlies and freezing levels rising to 1500 m. Tuesday: A ridge building over the regions should bring dryer and warm temperatures.

Avalanche Summary

Some natural avalanches were reported today, but the visibility was limited and there was very few observations. I suspect an avalanche cycle happened today, more details to come tomorrow.

Snowpack Summary

Up to 40 cm of storm snow was most likely very touchy today. The wind already started redistributing the snow and more windloading lee of strong westerly winds in the alpine and at treeline will keep avalanche conditions dangerous tomorrow. The new windslabs will most likely be very touchy and could possibly be triggered naturally. The storm snow is expected to have to potential to sluff in steep sheltered terrain. Cornices will continue building and could fall with this additional load. Avalanche professionals are still concerned that the facet/crust and surface hoar layer down between 70-100 cm and the depth hoar and basal facets situated at the bottom of the snowpack could be triggered. These persistent weak layers are showing a high spatial variability and also some variable snowpack test results. In other words, they are spotty and moody. The facet/crust layer at treeline has been mostly reactive on E aspects and the depth hoar layer in the alpine is still concern especially where the snowpack is thinner.

Problems

Storm Slabs

An icon showing Storm Slabs
Windslabs will keep developing lee of strong W winds and is be the main concern for tomorrow. Beware of the possibility of sluffing in steep sheltered terrain and of storm instabilities that could linger.
Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Persistent Slabs

An icon showing Persistent Slabs
Deep persistent instabilities could still be lingering in the snowpack and be triggered by a large load such as the windloading that is forecasted.
Be aware of the potential for large, deep avalanches due to the presence of buried facet/crust layer and depth hoar layer.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Jan 12th, 2014 2:00PM

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