Avalanche Forecast

Issued: Feb 14th, 2018 4:29PM

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

Avalanche Canada shorton, Avalanche Canada

New snow sits above a hard crust.  Be careful around terrain traps such as cliffs, trees, or gullies where a small avalanche could have severe consequences.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: Increasing cloud with flurries starting in the evening, moderate west wind, alpine high temperatures around -4 C.FRIDAY: 5-10 cm of new snow by the morning then clearing throughout the day, moderate northwest wind, freezing level climbing to 1000 m with alpine high temperatures around -2 C.SATURDAY: Heavy snow starting Friday night with 20-40 cm possible by the end of the day, strong west wind, freezing level climbing to 900 m with alpine high temperatures around -2 C.

Avalanche Summary

The new snow was reactive above the crust on Wednesday, including a report of a small avalanche on a steep north-facing convex roll. See here for photo. On Saturday, a cornice collapse was the likely cause of a size 2 avalanche on a north facing slope near the West Lion. See here for images and more details. Looking ahead, the storm slabs may remain reactive, so be suspicious of the bond between the new snow and crust.

Snowpack Summary

15-25 cm of storm snow sits above a hard rain crust at most elevations and above firm wind affected snow in the high alpine. It will take time for the new snow to form a solid bond with these varied surfaces - especially the rain crust. The average snowpack depth at treeline is 300 cm of well settled snow with no significant layers of concern.

Problems

Storm Slabs

An icon showing Storm Slabs
15-25 cm of fresh snow sits above a hard rain crust that extends well into the alpine. It may take time for the new snow to bond to the crust.
Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Choose well supported terrain without convexities.Be alert to conditions that change with elevation.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect. Give them a wide berth from above and below.
Give cornices a wide berth when traveling on or below ridges.Firm cornices may pull back into flat terrain at ridgetop if they fail.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 15th, 2018 2:00PM

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