Avalanche Forecast

Archived

Dec 27th, 2024–Dec 28th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

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.

Regions

Vancouver Island, East Island, North Island, South Island, West Island.

Another storm, another rapid uptick in avalanche danger. Enjoy another powder day in lower angled, low consequence terrain while the snowpack adjusts.

Confidence

Moderate

Avalanche Summary

Explosives control in the Mount Washington area produced several more size 1.5 - 2 wind slabs in west-facing terrain on Thursday.

Numerous size 1 - 1.5 slabs were observed throughout north-facing terrain in the same area Wednesday as well as a size 2 storm slab triggered accidentally by a skier walking along a ridgeline. It occurred on a northwest-facing 30-degree slope at treeline, fractured 100 m wide, ran 50 m, and featured a 40 cm crown.

Snowpack Summary

A wide-ranging 15 - 50 cm of new snow should accumulate by end of day Saturday. This adds to 40 - 60 cm of new snow from the Christmas storm. Accumulations in the west coast alpine may be significantly higher. Strong winds elsewhere have led to up to 200 cm sitting on the pre-storm crust!

Fluctuating freezing levels formed at least two mid-storm failure planes in the new snow, both of which produced moderate, sudden snowpack test results on Thursday. These weaknesses are expected to stabilize relatively quickly.

Below the new snow, the snowpack is thoroughly settled and bonded.

Snowpack depths at treeline are now about 130 -180 cm on the north and south island, closer to 250 to 300 cm on the central island.

Weather Summary

Friday Night

Cloudy with increasing snowfall bringing 10 to 30 cm of new snow, greatest in the west. 40 to 50 km/h southeast ridgetop wind. Freezing level 900 - 1100 m.

Saturday

Cloudy with continuing, increasingly wet flurries bringing 5 to 25 cm of new snow, greatest in the west. 50 to 60 km/h southwest ridgetop wind. Freezing level 1300 - 1400 m.

Sunday

Cloudy with scattered flurries bringing up to 5 cm of new snow. 30 to 40 km/h southeast ridgetop wind shifting southwest. Freezing level 1000 m.

Monday

Mainly cloudy with isolated flurries. 30 to 40 km/h southwest ridgetop wind. Freezing level 1100 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for fresh storm slabs building throughout the day.
Be especially cautious as you transition into wind-affected terrain.
Back off slopes as the surface becomes moist or wet with rising temperatures.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.