Avalanche Forecast

Archived

Mar 21st, 2025–Mar 22nd, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

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 possible, human triggered probable.

Regions

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

Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential.

Confidence

Moderate

Avalanche Summary

On Friday, explosive control in the region produced four size 2.5 persistent slab avalanches on northwest alpine features. A few dry loose avalanches were also observed up to size 1.5.

On Monday, two very large persistent slabs were remotely triggered by skiers and a snowcat in the Birkenhead area. They occurred on west and east alpine slopes and ran full path. Crowns were 75 to 100 cm and one of them stepped down to the mid-February week layer.

Snowpack Summary

15 to 30 cm of new snow and southwest winds reactive wind slabs on lee slopes at higher elevations. New snow overlies wind-affected snow at upper elevations and a melt-freeze crust on southerly slopes up to 2000 m. This sits over 80 to 150 cm of settling storm snow from the past week.

The early March weak layer of facets or surface hoar on a crust is now down 100 to 150 cm and is present on all aspects except high north-facing slopes. Very large avalanches (size 3 to 3.5) were reported on this layer in the past week.

Weak layers formed in mid-February and late-January are now buried 110 to 190 cm deep.

Weather Summary

Friday Night

Partly cloudy. 10 to 25 km/h southwest ridgetop wind. Treeline temperature -8 °C. Freezing level drops to valley bottom.

Saturday

Mix of sun and clouds. 15 to 25 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1200 m.

Sunday

Mostly cloudy with isolated flurries, 2 cm of snow. 30 to 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1600 m.

Monday

Mix of sun and clouds. 20 to 30 km/h southwest ridgetop wind. Treeline temperature +2 °C. Freezing level 2000 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.
Even brief periods of direct sun could produce natural avalanches.
Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
Be mindful that deep instabilities are still present and have produced recent large avalanches.

Problems

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.

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.