Avalanche Forecast

Archived

Feb 28th, 2024–Feb 29th, 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 avalanches possible, human triggered probable.

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

South Coast Inland, Birkenhead, Duffey, South Chilcotin, Stein, Taseko.

Very dangerous avalanche conditions continue at higher elevations. Avoid all avalanche terrain.

Natural and human-triggered avalanche activity remains likely.

Confidence

Moderate

Avalanche Summary

No new avalanches were reported by 4 pm on Wednesday. Poor visibility and high avalanche danger kept many users out of the backcountry.

We expect users who head out on Thursday will see evidence of a widespread natural storm slab avalanche cycle that occurred during the storm.

Several remotely triggered persistent slab avalanches were reported up to size two in the region early this week. This is a clear sign the persistent weak layer is primed for human-triggering.

Snowpack Summary

30 to 70 cm of storm snow overlies wind-affected surfaces and old wind slabs in exposed areas and settling snow in sheltered areas.

Multiple weak layers exist in the upper and mid snowpack. The most concerning weak layer is a widespread crust down 30 to 100 cm with a weak layer of facets or isolated surface hoar above this crust. This problematic layering is very concerning with recent large avalanche activity attributed to it. Although natural avalanche activity may taper out on this layer as the snow stops falling it will remain possible to human-trigger it for some time afterward.

Weather Summary

Wednesday Night

Cloudy with 15 to 20 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature rises to -7 °C. Freezing level drops to valley bottom.

Thursday

Partly cloudy with 1 to 5 cm of snow. 10 to 25 km/h southwest ridgetop wind. Treeline temperature -8 °C. Freezing levels around 800 m.

Friday

A mix of sun and cloud with 1 to 3 cm of snow. 10 to 25 km/h south ridgetop wind. Treeline temperature -10 °C. Freezing levels remain at valley bottom.

Saturday

Partly cloudy with 2 to 5 cm of snow. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -12 °C. Freezing levels remain at valley bottom.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.

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.