Avalanche Forecast

Archived

Jan 1st, 2021–Jan 2nd, 2021

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

South Coast.

Avoid avalanche terrain at upper elevations where it has not been raining as storm slabs are likely widespread.

At lower elevations where it has been raining, be aware of the potential for wet loose avalanches.

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

FRIDAY NIGHT - Rain and wet snow 15-30 cm/mm / southwest wind 60-80 km/h / alpine low temperature near 2 / freezing level 1400 m

SATURDAY - Rain and wet snow, 40-80 cm/mm with another 60 cm/mm overnight / southwest wind, 60-80 km/h / alpine high temperature near 3 / freezing level 1400 m

SUNDAY - Flurries, 10-15 cm / west wind 30-50 km/hr / alpine high temperature near -1 / freezing level 800 m

MONDAY - Wet snow, 10 cm / light southwest wind / alpine high temperature near 1 / freezing level 1200 m

Avalanche Summary

Slab avalanche activity is expected at upper elevations where the precipitation is falling as snow.

Wet loose avalanches may occur at lower elevations where the snow has been soaked by rain.

There were a few size 1-2 explosives triggered avalanches reported in the North Shore mountains on Thursday.

There were numerous avalanches up to size 1.5 reported in the North Shore mountains during the storm on Wednesday. It is likely that a widespread natural avalanche cycle occurred throughout the region on Wednesday as well, especially at higher elevations.

Snowpack Summary

Depending on elevation, the region may see between 50-110 cm of snow, or 50-110 mm of rain between Friday night and Saturday afternoon. It is likely that this precipitation will fall as rain on all but the highest terrain.

This will bring recent fresh snow amounts at upper elevations to as much as 200-250 cm, and the new snow sits on a crust in many areas, and may also sit on surface hoar in some places. At lower elevations, the snowpack will be rain-soaked.

The remainder of the snowpack is well-settled.

Terrain and Travel

Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
Avoid avalanche terrain during periods of heavy rain.
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.

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.