Avalanche Forecast

Issued: Jan 10th, 2023 4:00PM

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

Avalanche Canada jleblanc, Avalanche Canada

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Dangerous avalanche conditions exist at upper elevations as riders-triggered slabs are likely.

Watch for signs of instability like whumpfing, shooting cracks or recent avalanches.

Summary

Confidence

Moderate

Avalanche Summary

Numerous size 1 wind/storm slabs were human-triggered on steep terrain at treeline and above near Whistler. Natural avalanche activity was also reported, with small storm slabs and dry loose avalanches on steep terrain at treeline and below. On Monday, a skier accidentally triggered a small storm slab on south-west alpine lee feature near Blackcomb.

Snowpack Summary

Up to 35 cm of new snow has fallen into the region since Monday. Ongoing southerly and previous northerly winds have affected the storm snow in any open terrain and near ridgelines. On sheltered slopes, up to 70 cm of powder storm snow can be found. Snow is heavy and moist at lower elevations.

A thick widespread crust formed in late December is down 40 to 70 cm. In the alpine, it is thin and breakable. Professionals are concerned that small avalanches may run down to this crust and create larger-than-expected avalanches.

Near the base of the snowpack, a weak facet/crust layer from mid-November can be found and remains a concern for triggering with large loads or on thin spots. In general, the snowpack is weak, faceted, and shallow.

Weather Summary

Overcast skies and dry conditions are expected until a deeper system will push snowfall into the region early Thursday. Heavy precipitation and high freezing levels are forecasted until Saturday.

Tuesday night

Mainly clear, no precipitations, light southeasterly winds, freezing levels around 1200 m, low of -5C at treeline.

Wednesday

Increasing cloudiness, moderate southerly winds gusting 40 km/h, freezing levels around 1200 m, high of -2C at treeline.

Thursday

Stormy 15-35 cm of snow, rain at lower elevation, moderate southerly winds gusting 60 km/h, freezing levels around 1500 m, high of -1C at treeline.

Friday

Stormy 25-40 cmof wet snow, rain at lower elevation, moderate southerly winds gusting 60 km/h, freezing levels around 2000 m, high of +2C at treeline.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

Up to 30 cm of storm snow is found at upper elevations and reactive storm slabs have developed, especially on leeward terrain features where deposits are deep. Closely monitor the bonding of the new snow with the underlying surface. Be aware that slab avalanches could step down to deeper layers and produce larger-than-expected avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 11th, 2023 4:00PM