Avalanche Forecast

Issued: Dec 26th, 2020 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

Email

 Triggering wind slab avalanches is a possibility with the low density powder and uncertainty about if, when, and where wind has affected the snow.

 

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

SATURDAY NIGHT: Partly cloudy, light wind from various directions, temperatures around -10 C.

SUNDAY: Mostly cloudy, moderate southwest wind increasing throughout the day, temperatures around -8 C.

MONDAY: Isolated flurries with trace amounts of snow, moderate southwest wind, temperatures around -6 C.

TUESDAY: Cloudy with some isolated flurries, light south wind, temperatures around -8 C.

Avalanche Summary

With cold calm conditions over the past few days there have been some reports of dry loose avalanches from steep terrain (see the photo in this MIN report). The light powder is primed for forming wind slabs with any uptick in wind. If slopes haven't been impacted by wind yet, pay attention to any increase in wind in the upcoming days.

Snowpack Summary

Wind slabs are the main avalanche hazard to navigate right now, so pay attention to surface conditions especially if there are signs of active or recent wind loading. Buried wind slabs beneath the powder may also still be a concern. We are uncertain about if, when. and where wind has impacted the 30 cm of light snow that fell on Wednesday. Most weather stations have only showed light wind with the exception of some moderate northeast wind recorded near Tutshi on Saturday. Forecasts show some moderate southwest wind coming on Sunday.

A widespread melt-freeze crust now exists at an estimated 60-80 cm deep in the region. This crust has been reported up to 1400 m in the Wheaton Valley and up to 1800 m near the Alaska border. The lower snowpack is generally settled and strong, however there is potential for weak snow to persist at the bottom of the snowpack in colder, thinner snowpack areas such as the Wheaton Valley. 

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Avoid terrain traps where the consequence of any avalanche could be serious.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

Wind Slabs

An icon showing Wind Slabs

Any increase in wind speed will likely form wind slabs on the leeward side of ridges, ribs, and rolls. If you don't see obvious signs of wind slabs remember there may still be some buried wind slabs beneath the low density snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 28th, 2020 4:00PM