Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Triggering avalanches will be likely on terrain features that accumulate wind drifted snow near treeline and above treeline. Triggering avalanches in new storm snow will also possible. Avalanches have the potential to be large. Recognize where terrain traps such as rocks, trees, cliffs, and constricted features are in relation to where you are travelling; this type of terrain can greatly increase the consequence of getting caught in an avalanche. If you are unsure about the stability of the snowpack, stick to lower angle slopes less than 30 degrees steep to minimize your exposure to avalanches.  

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

     As more snow comes in overnight and Thursday combined with moderate winds, wind slabs will continue to build and avalanches will have the potential to be large. Remember that the wind can deposit snow many times deeper than the storm accumulation. Wind slabs are most sensitive to triggering when they are fresh and we could find these to be easy to trigger on Thursday. 

    Steep and convex terrain at and below ridge tops are the suspect places to trigger a wind slab but be cautious on any terrain feature that has accumulated blowing snow. As wind moves snow across open slopes, gully features in particular can become 'cross loaded' and filled in with new wind slabs. There can be a lot of variability associated with this problem; some lee slopes will have shallow windslabs while other slopes will collect a lot more blowing snow creating much deeper slabs. 

    There may be isolated pockets of weak faceted snow on steep north facing slopes under the new storm snow. Avalanches initiating on or stepping down to weak sugary snow may propagate wider and run farther than usual.

    Cracking in the wind deposited snow and recent avalanches are good indicators that you can trigger an avalanche, but remember we don't always get that feedback even when unstable snow exists. Wind slabs can be avoided by sticking to sheltered areas or slopes that have been scoured by the wind. 

    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.

    (3/12/2025)

    Shooting cracks were easy to come by on Wednesday.  Wind slabs were easy to trigger on lee features near treeline; several skier triggered size 1 avalanches were observed above east facing slopes. The crowns were up to 45 cm (18") deep, and that was from only 4" of storm snow. This picture is from an east facing slope near treeline.

    Photo: Aaron Hartz

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    The size of this problem will depend on how much new snow comes in overnight and on Thursday. As the storm totals exceed 20 cm (8") storm slab avalanches will begin increasing in size.

    Steep, convex, and unsupported features are the places where you are more likely to trigger a storm slab avalanche. 

    There may be isolated pockets of weak faceted snow on steep north facing slopes under the new storm snow. Avalanches initiating on or stepping down to weak sugary snow may propagate wider and run farther than usual.

    Dry loose avalanches are also possible.

Avalanche Discussion

Cornices will be building at ridgetops during this storm. Be cautious when approaching ridge tops. Avoid stepping out onto a fragile cornice and breaking through to the slope below. 

Regioni coperte