Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Another warm and clear day is on tap for the Mt Hood area, so look for warming snow and small wet loose slides on steep sunny slopes. As you gain elevation, look for signs of unstable snow in wind drifted areas. Steer around steep wind drifted slopes if you notice shooting cracks or hear snow that sounds hollow like a drum. 

Problèmes avalancheux

  • Loose Wet

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

    The strong March sun and warming temperatures will make the snow surface wet and weak on solar aspects (E-S-W). This will likely be more prominent at those middle and higher elevations where more soft snow exists. You’ll likely see these fan shaped slides on steep sunnies,  especially near rocks and cliffs. Consider steering around these areas if you notice rollerballs and pinwheels. These are often precursors of larger loose wet avalanches. This problem will likely be more prominent at those mid-elevations (and higher) that hold soft snow at the surface.  These should stay small, but still consider the consequence if they push you into a terrain trap such as trees or a gully bottom.

    (11/24/2022)

    Rollerballs like this are often indicators telling you the snow surface is becoming weak. 

    Photo: Robert Hahn

  • Wind Slabs

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

    Wind slabs are becoming harder to trigger with time, however not impossible. Our last significant loading event occurred Wednesday morning (3/15).  Many of these wind drifted slabs are likely on the firmer side due to radical wind speeds and could be quite consequential if triggered. 

    So as you more through the mountains,  be in tune with changing snow depths and texture. You’ll typically find these slabs lurking on the downwind side of ridges, under cornices, below cliff-bands, and near the top of chutes/couloirs.

    Look for active loading or slopes that appear textured and fat. Pillow-like slabs or ripples at the snow surface all indicate wind loaded terrain. You can use small test slopes to see how the slab reacts to your weight. And as always, pump the brakes if you notice shooting cracks under your skis/sled or hear snow that sounds hollow like a drum. 

    As the sun gets stronger, give cornices a wider margin. Warming temperatures are likely making these things a little weaker and easier to initiate. 

    (12/3/2022)

    A shooting crack in a stiff pocket of wind-drifted snow. Move away from steep wind-loaded slopes if you see signs like this. 

    Photo: Dallas Glass

Avalanche Discussion

On Thursday, I went to the Pea Gravel Ridge and used the ski area lifts to see several different aspects & elevations. On Pea Gravel, I noted another large (natural) avalanche on a SE aspect at 7300’. This avalanche likely occurred in the last 1-3 days during one of our loading events. Look at the picture in the gallery for more information. At lower elevations, I observed a widespread (mostly supportable) melt-freeze crust that extends to 5500’. Climbing higher in the terrain,  I observed chalky wind blown snow,  moist snow forming on west aspects, and sastrugi on windward slopes.  

High wind speeds this past week have built hard, stubborn slabs above treeline. This verified on Tuesday when the Meadows  Patrol triggered a large (D2.5) hard slab that broke 2-5 ft deep in one of their alpine bowls ( A-Zone 7200 ft, NE Aspect).  

If you get out let us know what you see by submitting an observation!

Régions couvertes