Avalanche Forecast

Issued: Dec 18th, 2015 8:00AM

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

andrew jones, Parks Canada

Glacier.

New snow and strong winds have contributed to a developing wind slab.

Summary

Weather Forecast

Light snow today with strong westerly winds and freezing levels remaining below 1000m. Expect 8cm of new snow accumulation by late Friday evening.

Snowpack Summary

20-30cm of snow covers a supportive crust below 1600m. 80cm of settled snow covers the Dec 2 interface, which is surface hoar below tree-line and a sun crust on steep, solar features at treeline and alpine. In exposed areas, the depth is variable due to wind-scouring. This layer may still be reactive to skiers in certain areas.

Avalanche Summary

Sluffing and skier triggered size 1's from sidewalls of steep gully features have been reported in the alpine. Several size 1.5 point release avalanches were observed in the Connaught area, triggered from steep rocky terrain. A size 2.5 natural slab avalanche had a long thin run of 1500m from cliffs below Teddy Bear Ridge in to the basin.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Watch for a developing wind slab in exposed areas as strong westerly winds transport recently fallen snow. Significant loading from wind transport can be expected in lee areas and may be easily triggered by riders.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

80cm of snow sits on top of the Dec 2 persistent weak layer, which is surface hoar at and below treeline and sun crust on solar aspects. Although this layer is becoming less reactive, it is still producing sudden results in stability tests.

Avoid shallow snowpack areas where triggering is more likely.Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 19th, 2015 8:00AM