Avalanche Forecast

Archived

Mar 18th, 2025–Mar 19th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Microwave-Sinclair, North Bulkley, South Bulkley, South Bulkley, South Bulkley, Telkwa.

Watch for fresh and reactive wind slabs forming at higher elevations on Wednesday.

Keep the buried weak layers on the radar, and head to simple terrain if you observe signs of instability.

Confidence

Moderate

Avalanche Summary

Rider triggered size 1 wind slabs were reported on Monday, during active loading from westerly winds at Ashman and Silvern Lakes.

Looking forward we expect this to continue with new snow and wind on Wednesday.

Snowpack Summary

Light snow and strong southwest winds are likely forming wind deposits on north facing slopes. A widespread layer of surface hoar is buried 10 to 30 cm deep, which overlies crust on solar aspects and at low elevations.

A layer of facets, surface hoar and/or a crust buried in mid February is 30 to 50 cm below the snow surface and has been reactive in snowpack tests.

Deeper in the snowpack, a weak layer of facets and a crust from early December can be found. This layer appears to be dormant but is still worth keeping in mind in thin snowpack areas in the alpine.

Weather Summary

Tuesday Night

Cloudy with flurries. 30 to 40 km/h southwest ridgetop wind increase overnight. Treeline temperature -5 °C.

Wednesday

Cloudy with up to 5 cm of snow. 50 to 60 km/h southwest winds at ridgetop. Treeline temperature -1 °C. Freezing levels reach 1100 m.

Thursday

A mix of sun and cloud with flurries 30 to 40 km/h southwest winds at ridgetop. Treeline temperature -0 °C. Freezing levels reach 1300 m.

Friday

A mix of sun and cloud with flurries 30 to 40 km/h southwest winds at ridgetop. Treeline temperature -0 °C. Freezing levels reach 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
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.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.