Bulletin d’avalanche

Central Cascades

Central Oregon Avalanche Center
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Danger d’avalanche

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

Points saillants

Avalanche danger will increase on Thursday. Triggering avalanches in new storm snow and wind drifted snow will be likely and avalanches can be large. This will be a day to check your terrain choice; the safe bet is to stick to slopes less than 30 degrees and avoid prominent convex features. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–2.5

    Wind slabs will build overnight and on Thursday. We have an abundance of new snow coming in combined with moderate to strong winds out of the southwest. Lee features below ridges and highpoints will be the likely suspects for triggering wind slab avalanches. Wind speeds will be sufficient to crossload slopes as wind wraps around features. Be cautious with your terrain choice and remember wind slabs are most sensitive to triggering when they are fresh. 

    Any time you see cracking in recent wind deposited snow or recent avalanches, recognize these as signs of unstable snow. 

    Use carefull evaluation in areas of sparse trees, clearings, and sections of dead forests. Open areas 'below treeline' can get enough blowing snow to create wind slabs.

     

     

    (12/25/2024)

    Cracking in wind slab on Wednesday. East aspect near treeline.

    Photo: Aaron Hartz

  • Storm Slabs

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

    Storm slab avalanches can happen anywhere the wind has not stripped the snow away. Steep, convex, and unsupported terrain are the likely features for triggering storm slabs. The low end of the weather forecast is calling for 18" of new snow by the afternoon on Thursday. The temperature will increase through the night and into the day, setting us up for the classic heavier over lighter storm snow. Signs of unstable snow such as cracking in the new snow and previous avalanches are great indicators that you can trigger a storm slab avalanche.

    Small dry loose avalanches will also be something to watch for, especially in steep and constricted terrain.

     

     

    Archive Photo:

    Example of a small storm slab avalanche.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    There is some weak snow around two rain crusts from late november and early december that are now down 3-5' in the snowpack (much deeper on wind loaded slopes). No natural or skier triggered avalanches initiating on these layers have been reported. It is unlikely that an avalanche will initiate on these layers. If an avalanche does happen at this depth, it would be catastrophic. 

Régions couvertes