Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Triggering a slab avalanche in wind deposited snow will be possible near and above treeline on lee slopes and triggering wet avalanches will be possible at the lower elevations on all aspects. Identify slopes that have been wind loaded and monitor depth of wind slabs. If you observe signs of unstable snow such as cracking in wind drifted snow, previous avalanches, or surface snow becoming slushy from rain, be aware that triggering an avalanche can occur on slopes 30 degrees or steeper.

Problemi valanghivi

  • Wind Slabs

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

    On Wednesday, blowing snow was observed in wind exposed areas and wind slabs were likely forming throughout the region. With around 4" of new snow on Wednesday and another 2-4" overnight, wind slabs will vary in depth with most resulting avalanches being small. Some isolated pockets of terrain that tend to catch more blowing snow could produce large avalanches. 

    Wind slabs form in specific areas where wind blown snow accumulates and are typically found below ridge tops, high points, and around features where cross slope winds deposit snow.

    Identify slopes that have been loaded using visual clues and look for pillowy drifts or a wavy surface texture. If you observe cracking in wind deposited snow or if you observe previous avalanches, increase your safety margin by sticking to slopes less than 30 degrees steep. 

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    This one will be very elevation dependent. Lower elevation areas like Santiam pass are expected to get rain throughout the night with up to 0.75" of rain possible by the morning. The higher elevation below treeline areas may only see light rain on Thursday morning and the wet avalanche problem will be unlikely in those areas. Observe how deep the snow is becoming saturated. As slushy snow becomes boot top or deeper, avalanches could become larger. Look for rollerballs and pinwheels as precursors to wet loose avalanches.

    Wet slab avalanches could also be possible as rain makes its way into snow layer interfaces in the upper snowpack. 

Avalanche Discussion

On Wedensday, the upper snowpack in non wind affected areas was found to be right sid up in structure. With small amounts of new snow coming in incrementally, storm slabs have not been a problem.

Cornices have been slowly building over the last week with continued snowfall and sustained southerly winds. Be cautious around cornices at ridgetops. Breaking through a cornice can result in a tumble and cornice breaks can send big chuncks of snow rolling down the slope below. 

Regioni coperte