Avalanche forecast

Sea To Sky

Jan 7 – 8, 2024Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The heavy dumping of fresh snow may need more time to stabilize. And also just barely cover lower elevation hazards.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    This problem is trending towards dormant, especially where a thick supportive crust is found down 40-100 cm (south of Whistler, this supportive crust reaches mountain tops).

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2

    30-60 cm snowfall in 48 hours will need time to settle and stabilize. Be suspect when transitioning into open and (previously) wind-affected terrain. At lower elevations, the snowpack may be below the threshold for avalanches.

Confidence

Moderate

Avalanche Summary

High winds and heavy snowfall limited observations late Friday. In the morning, explosives triggered storm slabs to size 1.5.

On Thursday, riders triggered avalanches to size 1.5 (10-30 cm thick) in the Whistler Backcountry. (see this MIN)

A crust deep in the snowpack (60-100 cm down) last produced avalanches Dec 31, and we suspect this layer is trending dormant.

Snowpack Summary

Over 50 cm in 24 hrs of snow accumulated by Saturday morning! Strong winds quickly impacted falling and loose snow, building reactive slabs and filling lees up to 100 cm deep.

Fresh and recent snow covers a crust buried Jan 1. 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.

Around 30-60 cm off the ground, facets or isolated surface hoar cover an early Dec crust. This layer is trending dormant with the last avalanches occurring on Dec 31st. Snowpack depths 80-150 cm around treeline and decrease rapidly below.

Weather Summary

Saturday Night

Mostly clear skies with no precipitation. Northwest ridgetop wind to 20 km/h. Treeline temperature -15 °C.

Sunday

Mostly sunny with no precipitation. Northwest ridgetop wind 5-15 km/h. Treeline temperature -10 °C.

Monday

Increasing clouds with light flurries. Southwest ridgetop wind increasing to moderate. Treeline temperature -8 °C.

Tuesday

Snowing, 25-50 cm starting late Monday. Strong southwest ridgetop wind. Treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • The new snow may require another day to settle and stabilize.
  • Closely monitor how the new snow is bonding to the old surface.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Be carefull with sluffing in steep terrain, especially above cliffs and terrain traps.

Regions covered