Avalanche Forecast

Archived

Mar 1st, 2024–Mar 2nd, 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, South Rockies, Akamina, Flathead, Lizard, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West.

The storm may have passed but dangerous avalanche conditions persist. The snowpack is primed for human triggering. Conservative decision-making remains critical.

Confidence

High

Avalanche Summary

Numerous natural, skier, and explosive-triggered avalanches up to size 3 have been reported over the last couple of days. Several of these avalanches have failed on or scrubbed down to a crust facet layer buried early in February.

Looking forward, it remains likely that humans could trigger high-consequence slab avalanches.

Snowpack Summary

Substantial snowfall associated with strong southwest wind and warming built storm slabs that likely remain touchy. These slabs have loaded weak faceted snow, surface hoar in wind-sheltered terrain, and a hard melt-freeze crust on sun-exposed slopes.

A widespread crust that formed in early February is buried around 80 to 120 cm deep. Weak faceted grains may be found above the crust, which is a recipe for high-consequence avalanches.

The remainder of the snowpack is generally settled.

Weather Summary

Friday Night

Cloudy with 0 to 5 cm of snow. 20 to 40 km/h southeast ridgetop wind. Treeline temperature -9 °C.

Saturday

Cloudy with 3 to 10 cm of snow. 30 to 50 km/h east ridgetop wind. Treeline temperature - 15 °C.

Sunday

Mostly cloudy with 0 to 4 cm of snow. 20 to 40 southwest ridgetop wind. Treeline temperature -12 °C.

Monday

Mostly cloudy with 0 to 5 cm of snow. 10 to 30 southwest ridgetop wind. Treeline temperature -10 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
Persistent slabs have potential to pull back to lower angle terrain.

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.