Avalanche Forecast

Issued: Jan 8th, 2021 4:00PM

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

Avalanche Canada ghelgeson, Avalanche Canada

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While the snowpack is slowly gaining strength in many locations, Pine Pass remains weaker than other locales. Wherever you go, watch for potentially deep wind slabs in exposed terrain and stay away from cornices. The best & safest riding will be found out of the wind.

Summary

Confidence

Moderate - Recent weather patterns have resulted in a high degree of snowpack variability within the region.

Weather Forecast

Reduced cloud cover for the next few days but quite a bit of west/southwest wind is in store.

FRIDAY NIGHT: Freezing level at valley bottom, strong west wind, trace of snow possible.

SATURDAY: A few clouds, freezing level at valley bottom, strong west/southwest wind, no snow expected.

SUNDAY: Scattered cloud cover, freezing level at valley bottom, strong southwest wind, trace of snow possible. 

MONDAY: Broken cloud cover, freezing level starting at valley bottom rising to about 1500 m during the day, strong southwest wind, trace of snow possible.

Avalanche Summary

Our field team found some recent avalanche activity in the Pine Pass on Thursday in the Bijoux area, more details here.

Snowpack Summary

The region received up to 55 cm from last weekend's storm, with the deepest amounts being found to the north. Up to 120 cm of settling storm snow can be found in the deeper drifts, this snow has all fallen in the New Year. The last storm was pretty warm, and you're likely to find a crust on the surface up to about 1100 m.

At this point 40 to 120 cm of snow is now sitting above a mix of weak interfaces that were buried in early December. This MIN provides a good illustration of that from one of the thinner snowpack areas in the region. Depending on location, the buried weak layer of concern is composed of weak surface hoar or weak crusts and facet layers which has created a persistent slab avalanche problem.

We do not see a clear pattern in which parts of the region or which types of terrain this problem is still a concern. 

Between Dec 18-20 there was compelling evidence of this problem around Pine Pass, the McGregors, and Tumbler Ridge. This problem has not been found at Renshaw, but has been found in the surrounding areas near McBride. There is no recent information from Kakwa. 

Overall, uncertainty about these layers make it difficult to have confidence in challenging or complex avalanche terrain without very careful terrain evaluation and an in-depth understanding of local snowpack conditions. We're firmly in a low probability high consequence scenario now.

Snow depths are 150-250 cm around Pine Pass, the McGregors, and McBride and closer to 100-150 cm around Tumbler Ridge. In shallower areas along the eastern slopes there is likely weak snow at the bottom of the snowpack that could be a concern in steep rocky alpine terrain.

Terrain and Travel

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • Be aware of highly variable recent wind loading patterns.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.

Problems

Wind Slabs

An icon showing Wind Slabs

West/southwest wind has been the theme for the last few days and it looks like plenty more is in store this weekend. The existing wind slabs are getting harder to trigger as they age and there isn't too much snow left to form into fresh slabs. That being said, the riding in wind affected terrain isn't great, and your best bet is to seek out wind sheltered terrain where you can avoid wind slabs and have a great day.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A persistent weak layer exists throughout the region 50-120 cm below the surface. In most places it looks like the overlying snow is gaining strength and human triggering is trending towards unlikely. However, areas around the Pine Pass seem to remain problematic and there has been some recent large avalanche activity on this interface.  

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 9th, 2021 4:00PM