Avalanche Forecast

Archived

Jan 28th, 2024–Jan 29th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kootenay Boundary, Lizard-Flathead, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, Ymir, Flathead, Crawford, Moyie, St. Mary, Kokanee, Retallack, Valhalla.

Avoid all avalanche terrain.

If the sun comes out in the afternoon expect another natural avalanche cycle.

Confidence

High

Avalanche Summary

Numerous large (size 2) slab and wet loose avalanches were reported on Sunday.

On Tuesday and Wednesday, there were also human-triggered persistent slab avalanches getting remotely triggered on the buried facets.

Snowpack Summary

The snowpack is losing strength and becoming soaked by rain and high temperatures.

The snowpack has two buried weak layers of concern:

A layer of facets and surface hoar buried 30 to 60 cm deep, covered by a thin crust at lower elevations but remaining active higher up.
A crust and facet combo from the new year down 80 to 100 cm. This layer seems to be becoming active now that it has a significant load over it from the continued trickle of snow.

Currently, the mid and lower snowpack is generally well-bonded, featuring a thick crust near its base.

Weather Summary

Sunday Night

Cloudy with no new snow, southwest alpine wind 30 km/h, treeline temperature 1 °C, freezing level 2250 m.

Monday

Cloudy with a trace of snow or rain, south alpine wind 35 to 50 km/h, treeline temperature 2 °C, freezing level 3000 m.

Tuesday

Mostly cloudy with 5 cm of snow, south alpine wind 45 to 60 km/h, treeline temperature 2 °C, freezing level 2000 m.

Wednesday

A mix of sun and cloud with no snow, south alpine wind 35 to 45 km/h, treeline temperature 4 °C, freezing level 2250 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Make conservative terrain choices and avoid overhead hazard.
Avoid steep convex slopes.
The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

Problems

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.