Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Fresh snow and wind will create dangerous conditions, particularly near and above treeline. Most avalanches will occur in the new snow, but some may step down to weaker snow above a crust to produce larger and more widely propagating avalanches. Avoid all wind-loaded slopes steeper than 35 degrees.

Problemi valanghivi

  • Wind Slabs

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

    Increased snowfall and winds will create more reactive snow. Moderate winds were blowing and transporting snow at higher elevations on Saturday. Winds will increase as we head into Sunday pulling the wind slab problem more into near treeline elevations.  Avalanches are expected to be widespread and in some cases, they may step down to weak snow above the 1/13 crust and run on the crust bed surface.  Firm layers with soft snow underneath, settlement under your feet, whumps, and shooting cracks are all signs of instability that remind you to dial back your terrain selection.  Avoid all wind-loaded slopes steeper than 35 degrees.

    Example: Wind textured snow surfaces and drifts like these serves as great clues that the wind affected the snowpack and may have formed wind slabs on nearby slopes.

  • Storm Slabs

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

    Storm slabs found in less wind-affected areas near and below treeline and with around a ft of snow expected in the next 24 hours, storm slabs could be reactive. Reactivity should peak during and shortly after periods of more intense snowfall. You can trigger them within the new snow or at the new-old snow interface. Keep in mind the potential that a storm steps down to weaker snow above the 1/13 crust to produce a large, dangerous, and widely breaking avalanche. Take advantage of small test slopes to gauge storm slab reactivity. Steer around convex rollovers steeper than 35 degrees.

    Example: Storm slab avalanche.

Avalanche Discussion

Mt. Hood picked up 4-5" of slightly denser snow in the last 24 hours with moderate winds above 7000 ft transporting significant snowfall. The recent snow sits above 10-15" of consolidating lower density snow that arrived in several installments over the course of last week. The stout mid-January crust is considered the new "ground" moving forward with a strong snowpack structure in place below this layer. Week snow (near-surface facets) are likely still present just above the stout crust. Weak facets identified above the 1/13 crusts were the likely culprit in a significant whumph observed around 7000 ft on a N aspect on the Cooper Spur.  We'll need to keep a close eye on this weak snow as we continue to add heavier, denser snow layers to the snowpack over the next several days. This facet-crust combination may start to be involved in more widely propagating avalanches if we reach a threshold.

Below 7000 ft., Hood Meadows patrol found isolated pockets of wind slabs on NE aspects on Friday and isolated loose dry activity on very steep terrain.  

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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