Avalanche Forecast

Issued: Jan 15th, 2016 8:52AM

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

Avalanche Canada triley, Avalanche Canada

Forecast snow and wind will continue to develop storm slabs. Strong winds may transport loose snow into deep pockets of wind slab.

Summary

Confidence

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

Weather Forecast

Light westerly winds and increasing cloud overnight with freezing levels at valley bottoms. Flurries or light snow combined with strong southerly winds on Saturday. Alpine temperatures rising slightly on Saturday to about -5. Continued strong southerly winds and light snow on Sunday. Skies clearing on Monday with light winds and no precipitation forecast. Alpine temperatures around -5.

Avalanche Summary

A natural avalanche cycle up to size 2.0 from various aspects was reported on Friday from west of Valemount. We had a report from Valemount on Thursday that in most areas the recent storm snow was mostly unconsolidated, and not reacting as a slab yet. In some areas the storm snow has been pressed into a slab by the winds and is very easy to trigger where it is sitting on a widespread layer of surface hoar. Expect soft storm slabs to continue to be triggered by human activity. We also had a report on Thursday from the Wells Grey area of a skier remotely triggering a size 2.0 slide that was 35 cm deep from 20 metres away. This avalanche was 80 metres wide and released on buried surface hoar in the alpine. This group also reported numerous whumpfs during the day. These reports suggest that there is some variability across the region. I suspect that the south and west of the region may have more storm snow, and the storm snow may have settled into a more cohesive slab in those areas.

Snowpack Summary

The recent storm snow total is now 10-30 cm. that is sitting on buried surface hoar and near surface facets. Some operations reported a thin freezing drizzle crust on the snow surface before the Wednesday morning snow arrived. Storm slabs and isolated wind slabs overlie old surfaces including surface hoar, facets, and possible sun crusts on steep southerly aspects. Below this, the upper pack is mostly drying out (through faceting). In general, the mid and lower snowpack are strong, with any weak layers considered dormant for now. Snowpack depths are variable and shallow snowpack areas may have weak facetted crystals near the ground.

Problems

Storm Slabs

An icon showing Storm Slabs
In areas where the storm snow has settled into a cohesive slab, the slab is easy to trigger and may allow for long fracture propagations due to the weak layer of buried surface hoar below. In other areas the recent snow may be unconsolidated.
Avoid freshly wind loaded features.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 16th, 2016 2:00PM