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 unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Coquihalla, Harrison-Fraser, Manning, Skagit.

As warm temperatures and sun heat up the snowpack, uncertainty around buried weak layers is best managed through conservative terrain choices.

Confidence

Moderate

Avalanche Summary

Recent avalanche activity has been mostly loose wet out of steep solar aspects, size 1-2.

Evidence of natural avalanches from the past weekend's storm is still visible throughout the region, with numerous very large (size 3.5 to 4) persistent slabs with impressive crowns (100 to 200 cm) in the Manning region.

Snowpack Summary

20 to 30 cm of recent snow sits over a crust, and is becoming moist or wet with warm temperatures and sun. At upper elevations, previous strong wind has redistributed surface snow, building wind slabs and cornices in lees.

A weak layer of facets and/or surface hoar is buried 50 to 120 cm deep. Large avalanches ran on this layer last weekend and it continues to give easy results in snowpack tests. We remain wary of it especially during these warm temperatures.

A crust from December, buried 1 to 2 m deep, has been observed to be breaking down.

Below 1300 m, the snowpack is saturated and disappearing quickly.

Weather Summary

Friday night

Clear. 10 to 20 km/h southwest ridgetop wind. Treeline temperature +5°C. Freezing level rising to 3200 m.

Saturday

Sunny. 20 to 30 km/h south ridgetop wind. Treeline temperature +6°C. Freezing level 3000 m.

Sunday

Mostly cloudy with 1 to 4 cm of snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature 0°C. Freezing level 1600 m.

Monday

Sunny. 20 to 40 km/h northeast ridgetop wind. Treeline temperature 0°C. Freezing level 1500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for large avalanches due to buried weak layers.
Back off slopes as the surface becomes moist or wet with rising temperatures.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
In times of uncertainty, conservative terrain choices are our best defense.

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.

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.

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.