Avalanche Forecast

Issued: Jan 5th, 2024 4:00PM

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

Avalanche Canada dsaly, Avalanche Canada

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Heavy snowfall and strong winds overnight - Expect to find a reactive storm slab by morning. Or fresh snow just barely covering lower elevation hazards.

Summary

Confidence

Moderate

Avalanche Summary

On Friday morning, explosives triggered storm slabs to size 1.5.

On Thursday, a few 1-1.5 slab avalanches were triggered in the Whistler Backcountry. Riders found reactive slabs 10-30 cm deep around ridges and in wind-loaded start zones. (see this MIN)

At the end of December, large and surprising avalanches failed over a crust down 50-100 cm (now deeper with new snow). Reports indicate this layer is becoming dormant, with no recent avalanches failing on this layer.

Snowpack Summary

10-20 cm of snow accumulated through Friday. Upwards of 30 cm of snow is forecast by Saturday morning.

10-30 cm of fresh and recent snow covers a crust that formed around the new year. This crust may exist up to mountain tops, and seems to be thick and supportive to the weight of a human south of Whistler, and more variable in thickness and strength to the north, where it thins out above 1900 m. Down 50-100 cm, facets or isolated surface hoar covers an early Dec crust. This layer last produced surprising avalanches on Dec 31st, however, recent reports suggest this layer is becoming dormant.

The lower snowpack is strong and bonded. Treeline snowpack depths 60-100 cm and decrease rapidly below treeline.

Weather Summary

Friday Night

Snowing. 20-40 cm of snow accumulating overnight. Very strong southwest ridgetop wind. Treeline temperature around -4 °C.

Saturday

Snowfall slowing early morning. Northwest ridgetop wind decreasing to moderate. Treeline low around -8 °C.

Sunday

A mix of sun and clouds. No precipitation. Light north ridgetop wind. Treeline low around -12 °C.

Monday

Cloudy with flurries, 5-10 cm snow. Increasing southwest ridgetop wind. Treeline low around -10 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Be careful to keep storm day fever from luring you out into bigger terrain features.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Problems

Storm Slabs

An icon showing Storm Slabs

Heavy snowfall and strong wind are forecast overnight and will add to recent snow. The touchiest deposits will be around ridges and in wind-affected terrain. At lower elevations, the snowpack may be below the threshold for avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

This problem is trending towards dormant, especially where a thick supportive crust is found down 20-40 cm (south of Whistler, this supportive crust reaches mountain tops). A heavy input of new snow may test this layer.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 6th, 2024 4:00PM

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