Avalanche Forecast
Issued: Jan 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
jleblanc,
Avalanche Canada
Watch for changing conditions throughout the day; slabs may become increasingly reactive.
The timing of the next storm is uncertain, but hazard will increase as the storm pushes in.
Summary
Confidence
Moderate
Avalanche Summary
Some small (size 1) human-triggered wind slabs avalanches were reported around Whistler on cross-loaded slopes on Friday. One of them has failed on a buried surface hoar layer underneath the recent snow. Avalanche control triggered several size 1-5 to 2 storm slabs on steep alpine lee features around Blackcomb/Whistler. A natural avalanche cycle up to size 2 has taken place Thursday night/Friday morning. These avalanches occurred on lee aspects at treeline and above.
Snowpack Summary
Up to 15 cm of new snow has fallen into the region since Friday. Ongoing southerly and northerly winds have affected the storm snow in any open terrain and near ridgelines. On sheltered slopes, up to 45 cm of powder storm snow can be found. Snow is heavy and moist at lower elevations.
In sheltered terrain at treeline, a weak layer of surface hoar is buried under the storm snow down 20 to 45 cm. A thick crust formed in late December is down 40 to 70 cm. At lower elevations, this crust is up to 15 cm thick. In the alpine, it is thin and breakable.
Near the base of the snowpack, a weak facet/crust layer from mid-November can be found and is still a concern. In general, the snowpack is weak, faceted, and shallow.
Weather Summary
A weak trough will continue to push moisture in the region Saturday night with a southerly flow aloft. On Sunday, another trough will generate periods of light snow until Monday night. Overcast skies and dry conditions are expected Tuesday.
Saturday night
Snow 5-10 cm, southeast winds easing gusting 45 km/h, freezing levels around 1500 m, low of -2C at treeline.
Sunday
Snow 5-10 cm expected in the afternoon, another 10-15 cm overnight, moderate southerly winds gusting 50 km/h, freezing levels around 1500 m; high of -2C at treeline.
Monday
Cloudy with flurries up to 5 cm, moderate southerly winds gusting 50 km/h, freezing levels around 1200 m, high of -3C at treeline.
Tuesday
Cloudy; lingering flurries, light southeasterly winds, freezing levels around 1000 m, high of -4C at treeline.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Conditions may have improved, but be mindful that deep instabilities are still present.
Problems
Wind Slabs
Fresh and reactive wind slabs will develop in lee features on northerly open slopes. Expect these may persist longer than normal, as they overlie a weak layer of surface hoar. Older wind slabs may still be found on various aspects due to last week's variable winds. Be aware that wind slab avalanches could step down to deeper layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A crust with weak, faceted snow above and below exists near the base of the snowpack. Human-triggering this layer is unlikely, but large loads such as cornice fall or a smaller avalanche stepping down to this layer are possible. Avoid thin, rocky, wind-affected areas where triggering this layer is most likely.
This layer is likely to be a concern for an extended period in this region. Read the new forecaster blog to learn more about this year's different snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 8th, 2023 4:00PM
