Avalanche Forecast

Issued: Dec 6th, 2022 4:00PM

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

Avalanche Canada lbaker, Avalanche Canada

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20 - 30 cm low-density snow and moderate ridge tops winds have redistributed into fresh wind slabs in open areas. As slabs continue to build watch for wind slabs becoming more cohesive and reactive in steep terrain.

Summary

Confidence

Moderate

Avalanche Summary

Shooting cracks and whumpfing is being reported at treeline. No new avalanches have been reported on the persistent weak layer. However, note that we have had very few field observations. There is great uncertainty around this layer and it has professionals guard up.

On Sunday operators in the region reported a natural windslab avalanche cycle to size 2 from the previous 24 to 48 hours.

Thank you for all the MIN reports! They are extremely helpful to us in the early season when snowpack information is limited. Please continue to share your observations via the Mountain Information Network

Snowpack Summary

20 - 30 cm of low-density snow has accumulated in sheltered areas at treeline. Where winds have redistributed fresh snow soft slabs are forming in lees. This overlies a variety of wind-affected surfaces.

A weak layer of surface hoar, facets, and melt-freeze crust can be found down 40-70 cm. This layer is more likely to be reactive where wind distribution has created a cohesive slab over it.

Snowpack depths range from 70 cm at treeline to 140 cm in the alpine. Below treeline snowpack is thin and faceted creating an additional challenge when accessing higher areas.

Weather Summary

Tuesday night

Cloudy skies and scattered flurries bring an additional 2 - 10 cm to the Cariboos. Valley bottom winds remain light but at ridgetop winds are strong from the northwest. Alpine temperature low of -10.

Wednesday

Cloudy with scattered flurries in the morning amounting to 2 - 5 cm through most of the region. Southwesterly ridge top winds 40 to 60 km/hr. Alpine temperature low of -5.

Thursday

A mix of sun and cloud and isolated flurries, accumulating trace amounts of snow. Ridgetop winds are 35 gusting to 50 km/hr from the southwest. Alpine high temperature -5 and a low of -10.

Friday

Sunny with cloudy periods and isolated flurries. Ridgetop winds are 40 km/hr from the west. Alpine high temperature -10 and a low of -15.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.

Problems

Wind Slabs

An icon showing Wind Slabs

With lots of loose snow for transport moderate to strong southwest winds have created wind slabs in lees. Watch for signs of instability such as whumpfing, cracking, and recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

The layer of concern formed mid-November is composed of faceted grains, surface hoar, and a hard crust and can be found down 40 to 70 cm. Each incremental snowfall and wind event is adding an additional load bringing the weak layer closer to its tipping point. As a cohesive slab builds above the weak layer it could quickly become reactive to natural or human triggers.

Aspects: All aspects.

Elevations: Treeline.

Likelihood

Unlikely

Expected Size

1.5 - 2.5

Valid until: Dec 7th, 2022 4:00PM

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