Avalanche Forecast

Issued: Dec 13th, 2014 8:01AM

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

ali haeri, Parks Canada

Glacier.

The storm has ended and temperatures are slowly cooling. The sun is expected to shine, the incoming solar radiation could be strong enough to trigger storm instabilities or cornices.

Summary

Weather Forecast

A high pressure ridge will keep the interior dry, cool and mostly clear for the next few days. Small disturbances will pass through the region but accumulation will be minimal. Winds are forecast to be light from the south.

Snowpack Summary

Cooler temperatures have tightened up the snowpack near the surface forming a crust with moist snow underneath it to ~2100m. Above 2000m is up to ~25cm of recent storm storm snow. Snowpack tests yesterday produced resistant planar results within the top 50cm. The Nov persistent weak layers are down ~100 and ~120cm.

Avalanche Summary

Avalanche control within the highway corridor west of the Rogers Pass summit yesterday produced mainly avalanches size 2.5 and up to size 3.0 showing wide propagation on the Nov 9 layer. Could not see all the results due to limited visibility. A backcountry natural avalanche cycle from a 2-3days ago from rain and warm temperatures is expected.

Confidence

Due to the quality of field observations

Problems

Storm Slabs

Storm snow layers up in the alpine are still suspect. We had 25cm of heavy snow over Dec 5 weak layer with strong winds. Some sunshine and the weight of a rider could be enough to trigger an avalanche.

Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Persistent Slabs

Big triggers like a cornice fall is capable of initiating this layer which would produce a very large avalanche as it would encompass the entire snowpack. Watch your exposure to overhead hazard like cornices when the sun comes out.

Cornices become weak with daytime heating.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Dec 14th, 2014 8:00AM