Avalanche Forecast

Issued: Jan 19th, 2017 4:30PM

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.

Continued unsettled weather with a gradual cooling.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

FRIDAY: Cloudy with isolated flurries, light south wind, alpine temperature -5, freezing level 800mSATURDAY: Mainly cloudy, wind light southeast, alpine temperature -4SUNDAY: Cloudy with sunny periods and the chance of isolated flurries, wind light south, alpine temperature -6More details can be found on the Mountain Weather Forecast.

Avalanche Summary

Recent reports indicate some explosives triggered avalanches to size 2 in the alpine on west and north aspects.

Snowpack Summary

10-30 cm of new snow accumulation, wind and warming have built wind slabs on wind-loaded features. In sheltered areas, the new snow has possibly buried a layer of feathery surface hoar. 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 still become reactive with the recent warm temperatures.

Problems

Wind Slabs

Recent new snow combined with southwest winds have created windslabs in the lee of terrain features

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Recent warming will have increased the likelihood of triggering persistent weak layers that have been lingering deeper in the snowpack

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 20th, 2017 2:00PM