Avalanche Forecast

Issued: Dec 10th, 2022 4:00PM

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

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The snowpack is thin, weak, and won't gain strength after a storm like it usually does. Stay conservative as you hunt for powder!

 

Summary

Confidence

Moderate

Avalanche Summary

Around the Whistler area on Friday size 1 to 2 soft storm slab avalanches were triggered with explosives, by skiers, and naturally. Interestingly, some explosives released size 2 on the mid-Nov crust down about 50cm and propagated around 50m wide.

Please keep sharing your observations via the MIN; it helps strengthen our information gathering!

Snowpack Summary

Surface: Around 20 to 30 cm of recent snow, but also at or near the surface you can find wind scoured, wind pressed, and of course wind slabs. In wind sheltered deep snow areas there could be as much as 70 cm storm snow accumulations.Upper-pack: on shaded terrain at all elevations large surface hoar (up to 10 mm) and generally unconsolidated snow. The upper snowpack consists of 20-50 cm of light but settling snow.Mid-pack: 50 cm down (maybe 70 to 100 cm in deep wind loaded areas) is a late November crust, with soft facets above. This is likely the critical snowpack weakness. Professionals are concerned about the possibility avalanches releasing at this deeper interface with the new snow load. So is Sofia (thanks for the MIN); I especially like her snowprofile photo!

Total snow depths remain low for early December with 90 to 140 cm at treeline and up to 200 cm in the alpine. Much of the below treeline elevation band is below the threshold for avalanches.

Weather Summary

Saturday NightStorm ends with only a trace to a few cm of snow overnight. Temps staying warm between -5 and 0 near treeline with freezing level around 800 m. Southeast to south wind moderate but diminishing overnight.

SundayDry with only a trace of snow possible. Continued warm with temperatures a few degrees below zero near treeline. Freezing level steady around 700 m. Light westerly wind. Mix of sun and cloud depending on location.

Monday

Dry. Cooler with temps between -5 to -10 C and freezing level to valley bottom. Northerly light wind with outflow from the interior through the passes and in the major valleys. Mix of sun and cloud clearing in the afternoon.

Tuesday

Similar to Monday but more sun and less cloud.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • The best and safest riding will be on slopes that have soft snow without any slab properties.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs could step down to the mid-November weakness in the middle of the snowpack.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Soft facets on a crust about halfway down into the snowpack may become more sensitive to triggering with additional snow. Small avalanches could step down to this layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Dec 11th, 2022 4:00PM