Avalanche Forecast

Issued: Jan 30th, 2022 4:00PM

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

Avalanche Canada astclair, Avalanche Canada

Email

Start simple and monitor the bond of the new snow with the hard crust. At upper elevations, carefully evaluate wind-drifted terrain and slopes with possible buried surface hoar. 

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Sunday night: Cloudy, 5-15 cm of snow, strong ridgetop winds shift from southwest to northwest, treeline low temperature near -12 C, freezing level drops to 100 m.

Monday: Cloudy with sunny breaks, isolated flurries with up to 5 cm of new snow, light northwest winds gusting to moderate at ridgetops, treeline high temperatures near -10 C, freezing level rising to 600 m. 

Tuesday: Sunny, no precipitation expected, light northwest winds, treeline high temperatures near -11 C, freezing level near 300 m.

Wednesday: Cloudy, scattered flurries with up to 5 cm of snow, moderate west winds, treeline high temperatures near -9 C, freezing level near valley bottom. 

Avalanche Summary

Avalanches in the new snow remain likely to trigger on Monday. 

There were few observations on Sunday. One operator in the south of the region reported several small (size 1) wet loose avalanches releasing naturally at lower elevations. 

Reports from the region are limited. If you head out into the mountains, please share any observations or photos on the Mountain Information Network.

Snowpack Summary

 

On Sunday, areas along the Duffey picked up 15-20 cm of new snow, while areas along the Coquihalla received up to 5 cm. Another 10-20 cm of snow is forecast to accumulate by Monday afternoon. The new snow is expected to form a widespread reactive storm slab problem that is particularly concerning where it sits over a layer of surface hoar. This layer has been reported in areas near Pemberton up to 1900 m and around the Coquihalla up to 1200 m. There is uncertainty as to whether the warm midday temperatures on Sunday were enough to break down the surface hoar in the south of the region. Stay disciplined with terrain selection, and closely monitor the bond of the new snow to previous snow surfaces. Be aware of the potential for loose avalanches in terrain where snow hasn't formed a slab.

Winds have been strong to extreme from the southwest, redistributing the new snow into stiffer wind slabs at upper elevations. Winds are forecast to shift to northwest overnight and ease to moderate. Anticipate changing slab conditions as you move into wind-exposed terrain on a variety of aspects.

Deeper in the snowpack, it is possible to find a crust/facet layer from December that is buried down 100-150 cm. This layer is most prominent between 1700-2100 m and is currently classified as dormant; although large loads such as a cornice failure or avalanches in motion may still be able to trigger avalanches on this layer.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Closely monitor how the new snow is bonding to the crust.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

Wind Slabs

An icon showing Wind Slabs

Strong southwest winds have redistributed the recent snow into stiffer slabs at upper elevations that are likely to be human triggered. Winds are forecast to shift to the northwest overnight, so watch for freshly formed slabs on a variety of aspects. Cornices may be reaching their breaking point. 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Storm Slabs

An icon showing Storm Slabs

15-30 cm of new snow has formed a widespread storm slab problem that will be especially reactive to human triggering in sheltered areas near treeline where large surface hoar sits over a crust. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 31st, 2022 4:00PM