Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Very dangerous avalanche conditions exist. Avoid avalanche terrain above 5500' and lower elevation slopes where large avalanches may reach from above. Below 5500' cautious route-finding and conservative decision-making will be essential.  Travel on ridgelines and low angled slopes staying away from cornices and slopes over 35 degrees where wind drifted snow has accumulated.

Problemi valanghivi

  • Wind Slabs

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

    Strong winds and heavy snowfall will build fresh and sensitive wind slabs into Thursday morning. Human triggered avalanches will be very likely on aspects collecting drifting snow, especially during the morning hours.  Larger avalanches will be more likely at upper elevations, where naturally triggered avalanches are likely as well. If you travel in the backcountry Thursday avoid travel in terrain connected to steep open slopes at higher elevations. Avalanches may run to valley bottoms. Give cornices wide berth and stay off slopes over 35 degrees where windblown snow has accumulated.  Firm and textured snow as well as cracking in the snow are signs you could trigger an avalanche.

    (12/18/2020) Debris from a large, natural, wind slab avlanche on Mt Hood.

  • Storm Slabs

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

    At lower elevations and in wind-sheltered areas use caution where you find more than 6 inches of recent snow.  Storm slab avalanches are most common during and just after periods of intense snowfall. Use small and inconsequential test slopes to examine the bond of the recent snow to the snow below. Look for evidence of heavier snow above light snow near the surface and cracking in the snow as you travel. Slightly warming temperatures may make storm slabs heavy and behave like wet loose avalanches. In either case, you'll want to navigate around slopes steeper than 35 degrees and avoid features such as convex rolls and unsupported slopes like those above cliffs or creeks.

    (12/13/2020) Cracking in the snow as you travel is a good sign of unstable snow.

Avalanche Discussion

The very large natural avalanches triggered on northerly aspects a week ago remain in the back of our minds. Given the heavy snowfall and rapid wind transport that this storm is bringing it is possible that similarly large slides may run long distances. Check out photos of the previous avalanche cycle in the media gallery. Practice safe transition points that are not exposed to large slopes from above.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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