Bulletin d’avalanche

Flathead

Mar 2 – 3, 2026Avalanche Canada
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Archivé · expiré 7 months ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

It's a challenging snowpack.

Strong winds have left slabs in open features, while persistent slab avalanches are most likely in sheltered areas at treeline and below.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Recent wind slab formation has been extensive, and stubborn slabs could extend into openings below treeline.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1.5–3

    Be aware of the potential for remote triggering and large avalanches due to buried surface hoar, especially at treeline and below. Watch for wet avalanches with sun and daytime warming, these could trigger the weak layer below.

  • Loose Wet

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

    Direct sun and daytime warming may trigger wet avalanches.

Confidence

Moderate

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

Avalanche Summary

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.

On Thursday, riders triggered a size 1.5 persistent slab on a steep slope from a treed ridge; the crown was 50 cm.

Snowpack Summary

Widespread wind effect has impacted 20 cm of recent snow, leaving a variety of pressed surfaces, slabs, and sastrugi in open terrain. Steep solar slopes may have a sun crust and turn moist during the day.

Within the top 80-120 cm of the snowpack, there are multiple concerning weak layers of surface hoar and/or crusts/facets. The majority of recent persistent slab avalanches have been on well-preserved surface hoar in sheltered areas at treeline and below.

The mid and lower snowpack are well settled.

Weather Summary

Sunday Night

Clear skies. 30 km/h west ridgetop wind. Treeline temperature -2 °C.

Monday

Sunny. 40 km/h west ridgetop wind. Treeline temperature 0 °C.

Tuesday

Mostly sunny. 1 to 3 mm of precipitation as snow or rain at treeline. 50 km/h west ridgetop wind. Treeline temperature -1 °C.

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.

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.
  • Keep your guard up at all elevations. Wind slab formation has been extensive and could extend into openings below treeline.
  • 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