Avalanche Forecast

Archived

Mar 19th, 2025–Mar 20th, 2025

Alpine

Natural and human triggered avalanches likely.

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Natural avalanches are expected as new snow and wind stress the snowpack.

Avoid any terrain with overhead hazard, persistent weak layers are capable of producing very large avalanches.

Confidence

Moderate

Avalanche Summary

Several natural persistent slab avalanches were reported on Monday, failing on the March surface hoar. Several stepped down to deeper weak layers producing avalanches up to size 3.

We expect this activity to continue with rapid loading from new snow and wind on Wednesday.

Snowpack Summary

Storm snow will accumulate over wind affected surfaces at higher elevations, with deeper deposits expected in north facing terrain features. Older wind slabs likely still linger below, found on all aspects. Lower elevations will receive a mix of rain and wet snow.

Two layers of concern currently exist in the upper-mid snowpack. Surface hoar on a crust can be found 50 to 90 cm deep. And a layer of facets, surface hoar and/or a crust from mid-February is buried 70 to 120 cm deep.

The remainder of the snowpack is well consolidated with no current concerns.

Weather Summary

Wednesday Night

Cloudy with 5 to 10 cm of snow. 30 to 50 km/h southeast ridgetop wind. Treeline temperature -4 °C.

Thursday

Cloudy with 1 to 3 cm of snow. 30 to 50 km/h south ridgetop wind. Treeline temperature -4 °C.

Friday

Cloudy with up to 5 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -5 °C.

Saturday

Cloudy with flurries. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -2 °C as freezing levels rise to 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Storm slab size and sensitivity to triggering will likely increase through the day.
Minimize exposure during periods of heavy loading from new snow and wind.
Avoid shallow snowpack areas, rocky outcrops, and steep terrain where triggering is most likely.
Be aware of the potential for large avalanches due to buried weak layers.

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.