Avalanche Forecast

Archived

Jan 26th, 2024–Jan 27th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

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 possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, South Okanagan, Ymir, Crawford, Moyie, St. Mary.

Persistent problems are best managed with patience and conservative terrain choices.

Choose terrain without terrain traps, free from overhead hazards.

Confidence

Moderate

Avalanche Summary

A few small (size 1) storm slab avalanches were triggered on Friday, with explosives.

On Thursday there were a few small (size 1-1.5) storm slab avalanches west of Winlaw. North aspect, treeline, 35 cm deep.

Numerous natural and human-triggered large (size 2) avalanches, 30 to 90 cm deep, were reported on Tuesday and Wednesday. Some were remotely triggered from far away. The activity was on all aspects, treeline and above, and often involved buried facets.

Snowpack Summary

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. This started as a storm slab and has persisted as a problem.
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

Friday Night

Cloudy with up to 5 cm of snow, southwest alpine wind 20 to 40 km/h, treeline temperature -4 °C.

Saturday

Cloudy with up to 5 cm of snow, southwest alpine wind 10 to 30 km/h, treeline temperature -2 °C, freezing level 1500 m.

Sunday

Cloudy with 15 to 20 cm of snow or rain, southwest alpine wind 30 to 50 km/h, treeline temperature 3 °C, freezing level 2700 m.

Monday

Mostly cloudy with 5 cm of snow or rain, south alpine wind 30 to 50 km/h, treeline temperature 4 °C, freezing level 3000 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.
Be carefull around freshly wind loaded features.

Problems

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.

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.