Avalanche Forecast

Archived

Feb 25th, 2024–Feb 26th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

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 unlikely, human triggered possible.

Regions

Lizard-Flathead, Akamina, Flathead, Lizard, Bull, Crowsnest South.

Dangerous avalanche conditions, natural and human-triggered avalanches are likely. Don't let storm day fever lure you into big terrain features

Confidence

Moderate

Avalanche Summary

On Saturday ski cutting produced numerous small avalanches in the reactive storm slab in the Lizard Range.

This MIN from last Thursday details a skier-triggered avalanche on the crust/facet layer found throughout the region.

With significant snowfall and strong wind in the forecast, the likelihood of both natural and human-triggered avalanches is primed to increase throughout the stormy period and remain elevated for several days.

Snowpack Summary

15 to 30 cm of new snow is expected to accumulate by the end of the day on Monday. This new snow will add to previous storm snow totals of around 20 cm.

Combined, the snow will be covering a sun crust on south and west-facing slopes and below treeline elevations. On north and east-facing upper-elevation slopes the storm snow and southwesterly winds are expected to form thicker and more reactive storm slabs.

A widespread crust formed in early February is buried 40 to 80 cm. In some areas, weak faceted grains have formed above and/or below the crust. The new snow may overload this layer creating very large avalanches.

Weather Summary

Sunday Night

Cloudy with 10 to 20 cm of new snow. 50 to 60 km/h southwest ridgetop wind. Treeline temperature -1 °C. Snow/rain line around 1200 m.

Monday

Mostly cloudy with 2 to 5 cm of snow. 25 km/h variable ridgetop wind. Treeline temperature -8 °C.

Tuesday

A mix of sun and cloud with 0 to 2 cm of snow. 5 to 15 km/h northeast ridgetop wind. Treeline temperature -15 °C.

Wednesday

Cloudy with 5 to 15 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level rising to 1500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Use increased caution at all elevations. Storm snow is forming touchy slabs.

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.