Bulletin d’avalanche

Flathead

Mar 3 – 4, 2026Avalanche Canada
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Archivé · expiré 7 months ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

It's a challenging snowpack that requires conservative terrain selection.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Recent wind slab formation has been extensive; check for stubborn slabs under ridges and in lee features.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3

    Be aware of the potential for remote triggering and large avalanches due to buried surface hoar, especially around steep openings in the forest.

Confidence

Moderate

  • We have higher uncertainty about treeline conditions due to persistent slabs.

Avalanche Summary

On Sunday, explosives triggered several persistent slab avalanches, many at treeline with 40 to 70 cm crowns.

On Saturday, skiers remotely triggered a size 1.5 avalanche from 30 m away while regrouping; it failed on surface hoar with a 55 cm crown depth.

On Friday, riders encountered extreme winds, whumpfing, and shooting cracks extending up to 200 m into lower-angle terrain. Snowpack tests found surface hoar buried 40-60 cm, with easy and reactive results.

Snowpack Summary

Widespread wind effect left a variety of pressed surfaces, slabs, and sastrugi in open terrain. Solar slopes have a crust and may turn moist during the day.

There are multiple weak layers of surface hoar and/or crusts/facets found in the upper 100 cm of the snowpack; the most reactive is 40 to 60 cm deep. The majority of recent persistent slab avalanches have been on well-preserved surface hoar in sheltered areas at treeline and below. While this persistent weak layer has been difficult to find near the ski area, riders continue to find it throughout the forecast region.

The mid and lower snowpack are well settled.

Weather Summary

Monday Night

Clear skies. 50 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1700 m.

Tuesday

Mix of sun and clouds. 60 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1600 m.

Wednesday

Mostly cloudy. 2 to 10 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1900 m.

Thursday

Mix of sun and clouds. 1 to 2 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • In times of uncertainty, conservative terrain choices are our best defense.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or recent avalanches.
  • Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
  • Limit exposure to steep, sun exposed slopes, especially when the solar radiation is strong.

Régions couvertes