Avalanche Forecast

Archived

Mar 21st, 2024–Mar 22nd, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Lizard-Flathead, South Rockies, Akamina, Flathead, Lizard, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West.

10 to 20 cm of new snow and west wind may have formed wind slabs on lee features at treeline and above.

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Confidence

Moderate

Avalanche Summary

No new avalanches were reported in this region on Wednesday.

Snowpack Summary

10 to 20 cm of new snow overies predominantly crusty surfaces, except for northerly aspects at upper elevations.

Westerly wind may have formed wind slabs on lee features at treeline and above.

A widespread, hard crust with facets above is buried 80 to 120 cm down in the South Rockies and up to 200 cm in the Lizard range. It continues to be the primary layer of concern for human triggering of very large persistent slab avalanches.

Weather Summary

Thursday night

Cloudy with isolated flurries, 0 to 5 cm snow. 10 to 20 km/h west ridgetop wind. Treeline temperature -8 °C. Freezing level valley bottom.

Friday

Mostly cloudy. 10 to 20 km/h west ridgetop wind. Treeline temperature -5 °C. Freezing level 1500 m.

Saturday

Cloudy with isolated flurries, 0 to 5 cm snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -10 °C. Freezing level 900 m.

Sunday

Cloudy. 30 to 40 km/h east ridgetop wind. Treeline temperature -12 °C. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
Cornice failure may trigger large avalanches.

Problems

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.

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.