Avalanche Forecast

Archived

Feb 28th, 2025–Mar 1st, 2025

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 possible, human triggered probable.

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

Northwest Coastal, Northwest Inland, Boundary, Stewart, Kispiox, Ningunsaw, Ningunsaw, Ningunsaw.

Natural avalanche activity may taper off, but the snowpack remains primed for human triggering.

Start with a very conservative trip plan and back off if you encounter signs of instability.

Confidence

Moderate

Avalanche Summary

The stormy conditions have proved a widespread natural avalanche cycle up to size 3. Many of these avalanches have been reported as wind, storm and persistent slabs at upper elevations and wet loose at lower elevations. Several human remote triggered (from 30 m afar) avalanches up to size 2 were reported.

Natural avalanche activity may taper, but conditions could remain primed for human triggering.

Snowpack Summary

Over the past few days strong southerly winds and up to 60 cm of new snow hit the region. Wind-transported snow has likely built deeper slabs on northerly aspects at upper elevations. Lower elevation snow may be crusty as freezing levels fall.

The upper metre of the snowpack is complicated. This snow sits above several significant weak layers that formed during the January and February dry spells. These include facets, surface hoar (in sheltered terrain), and crust on solar aspects. These layers are currently reactive.

Deeper in the snowpack, a weak layer of facets and a crust from early December varies in depth from 100 to 300 cm. This layer also remains a concern in this region.

Weather Summary

Friday Night

Cloudy with 5 to 10 cm of snow. 20 to 45 km/h south ridgetop wind. Treeline temperature -2 °C. Freezing level 1100 m.

Saturday

Cloudy with isolated flurries. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1200 m.

Sunday

Mainly cloudy with isolated flurries. 10 to 20 km/h west ridgetop wind. Treeline temperatures -1. Freezing level 1100 m.

Monday

Mix of sun and cloud. 10 to 20 km/h east ridgetop wind. Treeline temperatures -5. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Keep in mind that human triggering may persist as natural avalanches taper off.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Conservative terrain selection is critical; choose gentle, low consequence lines.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.