Avalanche Forecast

Issued: Jan 17th, 2017 4:24PM

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

mbender, Avalanche Canada

Purcells.

There is a lot of uncertainty surrounding the intensity of precipitation amounts in the region. Certainly in areas where the freezing level is forecast to rise in combination with the potential for snowfall, the avalanche danger will be elevated.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

WEDNESDAY: Flurries with 10-20 cm of accumulation, moderate south winds, freezing level rising to around 1500 m throughout the region.THURSDAY: Cloudy with isolated flurries, light to moderate southwest winds, freezing level around 1500m.FRIDAY: Cloudy with sunny periods, light southwest wind and freezing level 1300m.More details can be found on the Mountain Weather Forecast.

Avalanche Summary

Expect new snow and wind to build fresh and touchy wind slabs. Warming and and increased loading will also give a rise to the likelihood of triggering persistent slab avalanches.

Snowpack Summary

Expect 10-20 cm of new snow Tuesday night into Wednesday with greater accumulations in the southern part of the region. The new snow, wind, and warming will build touchy storm slabs that will be extra thick and reactive on wind-loaded features. In sheltered areas, the new snow is burying a layer of feathery surface hoar that may produce surprisingly wide propagations. The main concern deeper in the snowpack is a layer of sugary facets from mid-December that can be found between 50 and 100 cm deep. This layer was considered dormant during the recent cold weather, but may become reactive as warm temperatures soften the overlying slab.

Problems

Wind Slabs

Fresh wind slabs will build throughout the week and be reactive to human triggers. Be extra cautious in wind affected terrain.

Be cautious as you transition into wind affected terrain.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Minimize exposure during periods of heavy loading from new snow and wind.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Warming of the snowpack will increase the likelihood of triggering persistent weak layers that have been lingering deep in the snowpack.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Avoid steep, open slopes.Be cautious in shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Jan 18th, 2017 2:00PM