Avalanche Forecast

Issued: Jan 4th, 2024 4:00PM

The alpine rating is considerable, 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

Email

With a forecast of fresh snow falling with strong winds, expect to find an increasingly reactive snowpack and avalanche hazard highest at the end of the day.

Summary

Confidence

High

Avalanche Summary

On Wednesday, small soft slabs and cornices were reactive to explosives and skiers in the alpine.

On Tuesday in the Whistler area, a few small, human-triggered wind slab avalanches were reported in the alpine, some of them running far on a hard surface underneath.

At the end of December, large and surprising avalanches were occurring late over a crust down 50-100 cm, but this layer seems to be bonding, and no related avalanches have been reported in the new year.

Snowpack Summary

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 are sitting on another crust. This layer produced surprising avalanches late in December, but it appears to have gained strength, or is being shielded by the newer crust, and is now less of a concern.

The lower snowpack is strong and bonded. Treeline snowpack depths are in the 60-100 cm range, decreasing rapidly below treeline.

Weather Summary

Thursday Night

Cloudy. Up to 10 cm of snow by Friday morning. Moderate and increasing southwest ridgetop wind. Treeline temperature around -8 °C.

Friday

Snowing. 15-30 cm new snow accumlating by 4pm. Very strong southwest ridgetop wind. Treeline temperature around -5 °C.

Saturday

Cloudy. Up to 65 mm of precipitation in 48 hrs (falling as snow and ending early morning). Moderate west ridgetop wind. Treeline low around -6 °C.

Sunday

Mix of sun and clouds. no precipitation. Light northt ridgetop wind. Treeline low around -8 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

Problems

Storm Slabs

An icon showing Storm Slabs

Expect to find increasingly reactive slabs as fresh snow accumulates with strong and gusty southwest winds. Avalanche hazard will be highest at the end of the day.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

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 5th, 2024 4:00PM