Avalanche Forecast

Issued: Nov 26th, 2014 8:43AM

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

Avalanche Canada triley, Avalanche Canada

High avalanche danger. Deep storm slabs have developed quickly at higher elevations. Weak layers of sugary facets below the storm slabs has resulted in easy triggering of potentially large avalanches.

Summary

Confidence

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

Weather Forecast

A series of storms is expected to continue to move across the interior mountain ranges from the coast. Moderate to heavy snowfall combined with strong Southwest winds is forecast overnight and into Thursday morning. Temperatures are forecast to rise dramatically on Thursday, as the freezing level approaches 2000 metres. Some moisture is expected to remain trapped in the Southeast as the cold arctic air descends from the North and cuts off the low pressure at the Rockies. This should mean more snow on Friday, and maybe even some snow on Saturday. The long range picture is mostly clear and cold with Northeast winds; our uncertainty centers on the timing of the change from stormy to cold and clear.

Avalanche Summary

Observations have been extremely limited, although numerous size 1 storms slabs were observed in recent days in the Kootenay Pass area. Avalanche activity will likely increase in size and frequency with forecast wind, snow and rising freezing levels.

Snowpack Summary

As we begin our forecasting season we are working with very limited field data. If you have been out in the mountains, please send us a note with your observations to forecaster@avalanche.ca.Up to 70cm of storm snow has fallen over the past week, and continual storms are contributing to ongoing surface instabilities within the new snow. The developing storm slab is adding load to weak crystals at the base of the snowpack which formed during the recent dry spell. These weak crystals, which include facets, surface hoar and possibly crusts, become more reactive at higher elevations and may persist for some time with the potential for large and destructive avalanches.The limited field data that we have received suggests that there is not enough snow below treeline for avalanche activity.If you are sending us information, we are interested in snow depths at different elevations (alpine, treeline, below treeline), spatial extent of the crust/facet weak layer, and new snow/ storm snow amounts.

Problems

Storm Slabs

An icon showing Storm Slabs
The storm slab continues to develop with each new snowfall. Forecast warm temperatures and high freezing levels may settle the storm slab, causing it to become more cohesive and allowing for longer fracture propagations.
Good day to make conservative terrain choices.>Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Valid until: Nov 27th, 2014 2:00PM