Avalanche Forecast

Issued: Dec 29th, 2014 8:32AM

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

Avalanche Canada jlammers, Avalanche Canada

Check out the Tricky Holiday Conditions blog post for more details on the current avalanche scenario.

Summary

Confidence

Good

Weather Forecast

The dry ridge of high pressure will persist bringing mainly clear skies for the entire forecast period. Ridgetop temperatures should hover around -20 for each day, while ridge top winds will be mainly moderate from the northwest.

Avalanche Summary

We continue to get reports of skier-triggered, and remotely triggered slab avalanches. Avalanche activity has mostly been in the size 2 range, failing on the mid-December layers. With the current reverse loading pattern, I would expect a new round of wind slab activity on southeast through southwest facing terrain.

Snowpack Summary

Up to 35cm of low density snow fell over the last few days. This new snow, which overlies recently formed surface hoar, has likely been shifted by strong northerly winds into stiff and reactive wind slabs on south-facing terrain. Up to 90 cm below the surface, you'll likely find a touchy weak layer of surface hoar sitting on a thick rain crust. This buried snowpack structure was formed in mid-December and remains the primary layer of concern for the region. This widespread persistent weak layer continues to produce whumpfing and sudden snowpack tests, and will likely remain sensitive to human triggering for the foreseeable future. Although high elevation slopes may not have the rain crust, they are still reported to have touchy buried surface hoar. At the base of the snowpack, a crust/facet combo appears to have gone dormant for the time being.

Problems

Persistent Slabs

An icon showing Persistent Slabs
A persistent weak layer, buried up to 90cm below the surface, was responsible for a few close calls over the past week. The key to safe backcountry travel is in conservative terrain selection.
Use conservative route selection, stick to moderate angled terrain with low consequence and be aware of what is above you at all times as remote triggering is a concern.>Choose well supported, low-angle terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Wind Slabs

An icon showing Wind Slabs
Strong northerly winds have shifted loose surface snow into stiff wind slabs. Due to the reverse loading pattern, wind slabs may be found in unsuspecting locations.
Avoid travelling in areas that have been reverse loaded by winds.>Be cautious as you transition into wind affected terrain.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 30th, 2014 2:00PM

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