Avalanche Forecast

Archived

Dec 5th, 2023–Dec 6th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Coastal, Boundary, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson.

As the storm is easing off, keep your guard up, as slab formation has been extensive at treeline and above. Make conservative terrain choices and avoid overhead hazard.

Confidence

Moderate

Avalanche Summary

Natural avalanche activity continues, with small numerous loose dry on steep terrain and wet avalanches at lower elevations. Several large slabs (up to size 2.5) were triggered naturally and by explosives on northern alpine aspects.

Wind slabs and storm slabs were reactive to rider traffic on northerly slopes, as avalanches up to size 1.5 were triggered on a wind-loaded feature at treeline around 1300 m. They likely failed on the widespread crust up 50-100 m deep.

Snowpack Summary

The region received up to 45-80 cm of storm snow, which is rapidly setting with mild temperatures. Heavy rain has affected the snowpack below 1200 m.

In the alpine, strong southerly winds have redistributed this storm snow. A widespread crust, that varies in thickness and strength, is now found down 60 to 90 cm at 1600 m and below. The mid and lower snowpack appears to be well-bonded, but field observations have been limited early in the season. The height of snow at treeline is roughly 100-150 cm, and decreases drastically at lower elevations.

Weather Summary

The large frontal system will continue to track eastward, generating windy conditions. Scattered flurries are expected until Friday.

Tuesday night

Light snowfalls 5-10 cm. Southerly ridgetop winds gusting 90 km/h. Treeline temperatures near -4 °C. Freezing levels at 800 m.

Wednesday

Scattered flurries up to 5 cm. Moderate ridgetop winds up to 45 km/h. Treeline temperatures near -4 °C. Freezing levels at 800 m.

Thursday

Scattered flurries. Light ridgetop winds up to 25 km/h. Treeline temperatures near -6 °C. Freezing levels at valley bottom.

Friday

Isolated flurries. Light ridgetop winds up to 25 km/h. Treeline temperatures near -7 °C. Freezing levels at valley bottom.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid exposure to overhead avalanche terrain during periods of heavy loading from new snow, wind or rain.
Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
Seek out sheltered terrain where new snow hasn't been wind-affected.
The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.