Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Open full map
Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Slab avalanches in wind drifted snow still pose a risk to backcountry travelers near and above treeline. Use lower angle terrain to navigate around steep features where you are more likely to trigger an avalanche.

Problèmes avalancheux

  • Wind Slabs

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

    Strong winds and new snow over the weekend created unstable wind slabs in above, near, and even some below treeline areas. Specific terrain features like convex breakovers, hanging slopes above or around cliffs, and very steep terrain below ridgelines are the most suspect. Unstable wind slabs last longer in the vicinity of these trigger points. Getting caught in even a small avalanche in steep rocky or treed terrain can have high consequences.

    Look for prominent signs of wind transport like cornices, scoured ridgelines, and large pillowy drifts to help locate wind slabs. Pay attention to areas where your flotation of choice is staying closer to the snow surface on a dense supportable slab vs. moving through soft new snow. 

    Pillowy drifts? Check . . . Unstable wind slab? 

    Photo: Dallas Glass

Avalanche Discussion

Update Monday @ 8:50:  Observation from Canyon Creek indicating small snowmobile triggered avalanches in wind loaded terrain near treeline. 

A widespread natural avalanche cycle occurred on Saturday sparked by 2’ of new snow, rising freezing levels, and very strong winds. Excellent visibility on Sunday allowed for observations well up into the alpine with many natrural avalanches to D3 noted on all aspects. Some avalanches also ran well down into below treeline terrain as noted here. 

With clear skies and sun came observations of minor loose wet avalanche activity on southerly aspects. Similar terrain will likely sport a refrozen crust in the coming days.  A new crop of surface hoar was noted on shady slopes.

On Monday expect cloudy skies and light winds. Stable weather in the next 24 hours will have little impact on avalanche danger other than giving lingering, unstable slabs more time to gain strength before the next storm.

Régions couvertes