Avalanche Forecast

Archived

Feb 26th, 2024–Feb 27th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Bonnington, Grohman, Kootenay Pass, Norns, Ymir, Crawford, Moyie, St. Mary, Kokanee, Valhalla.

Recent storm snow needs time to gain strength and stabilize, while a buried crust remains a major concern.

Confidence

Moderate

Avalanche Summary

A remotely triggered size 3 avalanche was triggered on Monday just west of Kimberley. The avalanche was triggered from a ridgetop approximately 20 m away, propagated roughly 300 m, and was 30 cm deep on average. It is suspected this slide occurred on the buried crust/facet layer.

Numerous natural, skier, and explosive-triggered avalanches occurred on Sunday throughout the region. Avalanches occurred in upper treeline and alpine terrain on various aspects, sized 1 to 2.

Snowpack Summary

The recent storm brought significant snowfall at higher elevations, which has been redistributed by strong alpine winds. Around 30 cm of snow now sits atop a variety of preexisting surfaces in the upper snowpack. These surfaces include sun crusts on south-facing slopes and faceted snow or surface hoar in sheltered, north-facing terrain.

A widespread crust exists down roughly 50 to 80 cm. In many areas, small, weak faceted grains have formed just above or below this crust.

The mid and lower snowpack is generally well settled.

Weather Summary

Monday Night

Partly cloudy with 0 to 2 cm of snow. 20 to 30 km/h west ridgetop wind. Treeline temperature -12 °C.

Tuesday

Sunny with cloud building in the afternoon. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -12 °C.

Wednesday

Cloudy with 5 to 20 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level 1500 m.

Thursday

Cloudy with 10 to 20 cm of snow. 40 to 60 km/h southwest ridgetop wind. Freezing level 1500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Good day to make conservative terrain choices.
Give the new snow several days to settle and stabilize before pushing into bigger terrain.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avoid areas where the snow feels stiff and/or slabby.

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.

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.