Avalanche Forecast

Archived

Jan 5th, 2021–Jan 6th, 2021

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

South Coast.

Heavy snowfall combined with strong to extreme wind overnight Tuesday will push avalanche danger to high at upper elevations. Give the new snow time to stabilize.

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

Tuesday Night: Heavy snowfall or rain, accumulation 20-40 cm, strong to extreme southwest wind, treeline high temperature 0, freezing level 1100 m.

Wednesday: Mainly cloudy, strong wind easing to moderate southwest, treeline high temperature 0, freezing level 1200 m.

Thursday: Sun and cloud, lightto moderate southwest wind, treeline high temperature 2, freezing level rising to 1500 m.

Friday: Snow or rain, moderate southwest wind, freezing level 900 m.

Avalanche Summary

There are no recent avalanches to report, although I would expect an increase in storm and wind slab avalanche activity at upper elevations overnight Tuesday and very early morning Wednesday. As well, lower elevations may see an increase in wet loose activity in steep terrain below the 1100 m elevation band.

Snowpack Summary

Precipitation arriving Tuesday afternoon and evening was expected to arrive as snow at uppermost elevations. Recent storm totals for the last week at upper elevations are upwards of 200 cm. This snow has likely seen extensive wind effect but we have received no alpine observations. Recent snow may contain and/or sit on a crust. At lower elevations, the previously rain soaked mid to lower snowpack will be dense and refrozen, or still wet below 1000 m.

The remainder of the snowpack is well-settled.

Terrain and Travel

Dial back your terrain choices if you are seeing more than 30 cm of new snow.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Be especially cautious as you transition into wind affected terrain.
Avoid lee and cross-loaded terrain.

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.