Avalanche Forecast

Issued: Dec 25th, 2016 8:00AM

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

percy woods, Parks Canada

Glacier.

Happy Holidays! Watch for signs of storm slab formation. Consider avoiding steep solar aspects this afternoon if the sun comes out.

Summary

Weather Forecast

A mix of sun and cloud today with light winds and alpine temperatures remaining cool around -12C. A SW flow should bring 20cm of storm snow through Tuesday evening accompanied by light to moderate SW winds. Expect a rising avalanche danger as the week progresses.

Snowpack Summary

In the past week 100cm+/- storm snow has fallen at treeline elevation. The storm snow is slowly settling into a slab over the Dec 18th facet/surface hoar layer down around 60cm. In many areas the storm snow remains loose and unconsolidated. Watch for signs of the storm snow settling into a slab.

Avalanche Summary

Nine avalanches observed out of steep terrain in the highway corridor in the last couple days. Friday there was a report from treeline on Avalanche Crest of small convex rolls shearing off down 50cm, likely at the Dec 18th interface.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Strong SW wind during last week's storm formed windslab in the immediate lee of ridges and cross loaded features. Field tests Thursday confirmed the slabs could be reactive to skier loads around ridges.These slabs may be hidden by Friday's snowfall.

Use caution in lee areas. Recent wind loading have created wind slabs.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

The recent storm snow has been slow to form a slab in part due to continued cool temperatures. Slab properties are starting to form and this is a concern given the Dec 18th facet/surface hoar weak layer down 50-60cm.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Avoid unsupported slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 26th, 2016 8:00AM