Avalanche Forecast

Issued: Dec 23rd, 2017 8:02AM

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

ian gale, Parks Canada

Glacier.

A spotty surface hoar layer is buried by a settling slab. Pay attention to cracking and whumphing as you travel.

Summary

Weather Forecast

A strong ridge of high pressure is sitting over much of BC giving us clear sunny skies. The winds will be from the West in the15-25km/hr range with an Alpine high of -18C... bbrrr thats cold, bring an extra layer or two! The ridge of high pressure looks like it will persist until later next week, with no snow in the forecast until next Friday.

Snowpack Summary

40-50cm of settling snow sits on the Dec 15 surface hoar, persistent weak layer. On steeper solar aspects this layer is a crust and/or a crust with small surface hoar on top. In the alpine variable winds have been redistributing recent snow. Deeper in the snowpack there are a series of crust layers that are currently bonding well.

Avalanche Summary

Numerous natural avalanches over the past few days up to sz 2.5 from steep terrain. The artillery control shoot earlier in the week produced avalanches to size 3 that were showing wide propagation in the start zones where the slab was cohesive.

Confidence

Wind speed and direction is uncertain

Problems

Persistent Slabs

Recent storm snow is settling into a persistent slab. Expect the slab to be more sensitive as you transition into steep and/or wind effected terrain. South and West aspects have a thin crust layer below the slab and a facet/surface hoar combo BTL.

Watch for whumpfing, hollow sounds, and shooting cracks.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Moderate variable winds are forming reverse loaded wind slabs in wind exposed areas in the Alpine and at tree line. These slabs may have surface hoar or crust underneath leading them to be sensitive to human triggering.

Keep an eye out for reverse loading created by N-NE winds.Watch for signs of instability such as whumpfing, or cracking.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 24th, 2017 8:00AM