Avalanche Forecast

Issued: Jan 18th, 2017 4:43PM

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.

It will take a few days for the most recent storm snow to settle.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

THURSDAY: Cloudy with isolated flurries, accumulation 5cm, light to moderate southwest winds, Alpine temperature -7FRIDAY: Cloudy with sunny periods, light south wind, alpine temperature -8SATURDAY: Mix of sun and cloud, wind light southeast, alpine temperature -8More details can be found on the Mountain Weather Forecast.

Avalanche Summary

No new significant avalanche activity to report. Warm temperatures and the recent increase in load will give a rise to the likelihood of triggering persistent slab avalanches.

Snowpack Summary

10-20 cm of new snow accumulation, wind, and warming have built touchy wind slabs 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.

Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

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.

Be cautious in shallow snowpack areas where triggering is more likely.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Jan 19th, 2017 2:00PM