Avalanche Forecast

Archived

Feb 21st, 2025–Feb 22nd, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

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 possible, human triggered probable.

Regions

South Coast, Powell River, North Shore, Sky Pilot, Tetrahedron.

Heavy precipitation combined with warm temperatures create very dangerous avalanche conditions. Natural avalanches are likely, and human triggered avalanches are very likely.

Confidence

Moderate

Avalanche Summary

Recent explosive control produced small storm slab avalanches on the North shore.

Over the weekend, the new storm snow was showing poor bonding to underlying weak layers. As the storm snow continues to pile up, these layers may produce large avalanches.

Snowpack Summary

Up to 70 mm of precipitation has fallen across the coast over the past three days. In sheltered terrain this new snow may overlie soft, faceted snow or surface hoar. In exposed terrain it will overlie a sun crust or wind-affected snow.

A late-January weak layer (hard crust, facets, or surface hoar) is buried 80 to 120 cm deep, this layer could become reactive the more the precipitation adds load on it.

The lower snowpack is strong and bonded.

Weather Summary

Friday Night

Cloudy with 20 to 40 mm of mixed precipitation. 40 to 60 km/h southwest ridgetop wind. Freezing level 1600 m.

Saturday

Cloudy with 40 to 60 mm of precipitation. 40 to 80 km/h southwest ridgetop wind. Freezing level rising to 2000 m.

Sunday

Cloudy with 10 to 15 mm of precipitation. 40 to 70 km/h south ridgetop wind. Freezing level 1800 m.

Monday

Cloudy with 30 to 50 mm of precipitation. 40 to 70 km/h southwest ridgetop wind. Freezing level 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Closely monitor how the new snow is bonding to the old surface.
Be aware of the potential for large avalanches due to buried weak layers.
A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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.