Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Wind-affected snow abounds in exposed terrain on Mt. Hood, but avalanches are becoming more stubborn. Focus your attention on wind-loaded, steep, and unsupported upper-elevation slopes where you can still trigger a large avalanche. Look for blowing snow as a sign of slab development as winds increase during the day and create small slabs that will be most consequential in extreme terrain features.

Problèmes avalancheux

  • Wind Slabs

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

    Sunday's round of 6-8" of snow and SW winds appears to have produced widespread wind-affected snow, but slabs have been limited in size and reactivity. We still think you can trigger one of these slabs on Tuesday, but reactivity should primarily be on steep rollovers in wind-loaded terrain. As winds pick up in the afternoon your focus should shift to active snow transport. Blowing and drifting snow will help you navigate around lens-shaped pillows developing on the lee sides of ridges. If these pillows accumulate 6" of drifted snow, they will be reactive to human trigger. The size and extent of slab development will increase with elevation, wind speed, and in the event that any appreciable snow falls out of the sky.

    A shallow human-triggered avalanche today on Hogsback serves as a reminder that careful snowpack evaluation is necessary on the upper slopes of Mt Hood where NWAC forecast ratings don't apply. 

    (12/5/2022)

    Shallow large skier-triggered wind slab on the upper slopes of Mt. Hood (Hogsback). Wind ripples nearby illustrate significant wind transport.

    Photo: Bjarne Salen

Avalanche Discussion

Mt. Hood Meadows Pro Patrol found slabs losing some reactivity to human trigger, but were still able to trigger a few small avalanches in previously unmitigated upper-elevation terrain. 

Sunshine on Monday may have formed surface crusts on sun-baked aspects by the time you head out on Tuesday. Sunday's snow added to previous cold snow layers. During Saturday's clear weather, observers documented large natural avalanche activity above treeline from a major storm cycle from November 27 - December 1st. You can find an assortment of photos from this storm cycle in the photo reel. On some southerly aspects, you may find a thin crust buried by the snow 12/4. These thin, aspect-dependent crusts exist within cold snow layering that comprises the upper 50-75% of the snowpack with thicker crusts buried after a dry spell in mid-November.

If you get out this week, please submit an observation on our public observation platform!  These observations play an integral role in producing a quality avalanche forecast, but also help the greater backcountry community.

Régions couvertes