Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

You can trigger a small wind slab where winds easily transport fresh, low-density snowfall into slabs 6" or deeper. At upper elevations, older slabs are gradually healing, but continue to steer around unsupported rollovers in the terrain where the consequences of a large avalanche warrant precaution. Early season hazards remain your primary concern at lower elevations.

Problemi valanghivi

  • Wind Slabs

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

    Fresh snowfall and wind will drift snow into small slabs you can trigger on a steep slope. You can look for active snow transport, fresh and sharp wind lips or cornices, and textured chalky snow to identify areas where you might want to steer clear of slopes 35 degrees or steeper.

    In most exposed terrain, firm older slabs are becoming stubborn to trigger. Evidence of large natural avalanche activity in Superbowl came at the end of a large recent storm cycle (likely Wednesday) and reminds us that wind slabs may be reactive up to 5 days after a storm. These slabs may underly the softer slabs forming on the surface. You can probably only trigger them on steep, convex rollovers at the upper elevations. 

    Example: Blowing snow and deposition on the lee side shows "texture" where the slab is building. Steer around such loading patterns on Sunday. 

    Photo: Robert Hahn

Avalanche Discussion

A major storm cycle from November 27 - December 1st brought much of the season's snowpack to date, along with very strong westerly winds. Information had been scarce on the upper mountain, however with clear weather on Saturday, observers documented large natural avalanche activity above treeline - likely from the tail end of the storm cycle.  The winds have eased over the last 48 hours, allowing older slabs to gain strength, making them unlikely, but consequential to trigger.  Sunshine on Saturday touched off some minor wet loose avalanche activity on steep south-facing slopes and may form a thin crust on some aspects for Sunday. This could be a useful marker when examining the transport of 2-6" of low-density snow arriving with enough wind to move snow on Sunday.

Although moderating temperatures have allowed recent snow to slowly settle, keep your partner in sight as snow suffocation is a real hazard.  Keep your partners in sight and give tree wells an extra buffer.  Keep in mind that rocks, roots, and trees can be found within the recent gradually consolidating snow.

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

Regioni coperte