Avalanche Forecast

Archived

Feb 27th, 2024–Feb 28th, 2024

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 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.

Regions

North Columbia, South Columbia, Esplanade, Jordan, North Selkirk, West Purcell, Badshot-Battle, Central Selkirk, Goat, Gold, Retallack, Whatshan.

More snow and wind arriving Wednesday means avalanche danger will be High. Persistent slab avalanches are primed for rider triggering.

Confidence

Moderate

Avalanche Summary

Numerous natural and rider triggered storm slab and persistent slab avalanches size 1 to 3 have been reported the past few days in the alpine and treeline elevation bands. One rider triggered persistent slab avalanches resulted in a full burial/recovery east of Revelstoke. Persistent slabs were mostly on north to west aspects and 60 to 100 cm deep. Some of these avalanches were remotely triggered (from a distance).

Expect persistent slab avalanche activity to continue.

Snowpack Summary

60 to 90 cm of recent snow sits on a variety of layers that it may not bond well to, including surface hoar in wind-sheltered terrain, weak facets, or a hard melt-freeze crust on sun-exposed south and west-facing slopes. The wind has likely formed thicker deposits in lee terrain features near ridges.

A thick and hard widespread crust that formed in early February is buried 60 to 120 cm deep and is found up to around 2400 m. This crust may have a layer of facets above it, which makes it a troublesome avalanche layer.

The remainder of the snowpack is settled.

Weather Summary

Tuesday Night

Cloudy with 5-10 cm of snow. 20 to 50 km/h southwest ridgetop wind. Treeline temperature -10 °C.

Wednesday

Cloudy with 10 to 20 cm of snow. 30 to 60 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1500 m.

Thursday

Cloudy with 15 to 30 cm of snow. 30 to 60 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1400 m.

Friday

Mostly cloudy with 3 to 5 cm of snow. 15 to 40 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Minimize exposure during periods of heavy loading from new snow and wind.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

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.

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.