Bollettino valanghe

Mt Hood

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Nearly five inches of mostly liquid water will impact Mt. Hood, creating very dangerous conditions Saturday night through Sunday. Wet snow avalanches could be large enough to destroy a house. Avoid all avalanche terrain. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    2–3

    The weather and avalnche danger has been unrelenting at Mt. Hood and the danger within this multi-day avalanche cycle should peak Saturday night and Sunday. We're 4-5 inches of water to hit the snowpack in 24 hours, we have high confidence that there will be very dangerous avalanche conditions. The character and distribution of avalanche problems are more difficult to predict. We expect widespread large natural and human-triggered Wet Loose avalanches which may or may not gauge through recent freezing rain crusts observed up to 6600 ft. We expect less frequent very large Wet Loose avalanches, particularly above 6600 ft. We are particularly concerned about the ability of slopes above 5500 ft to handle the addition of weight and the potential for water to percolate down and trigger weaker snow above the 12/9 crust.  Sunday is a good day to avoid the mountains and if you must be out, avoid all terrain where avalanches can start, stop, or run.

    Example: Large loose wet avalanche.

  • Wind Slabs

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

    With snow levels forecast to rise to 8000 ft, dry snow problems will redevelop at the upper reaches of our forecast area on Friday as snow levels lower to around 7000 ft. We expect there to be enough new snow and wind to regenerate the potential for large wind slabs quickly on Sunday. Of even greater concern may be the potential for very large wind slab avalanches initiating above our forecast area to impact travelers at any elevation. Two very large natural wind slab avalanches observed Friday (details in the discussion below) remind us of the scale of these avalanches (which could be even larger on Sunday). Don't try to nuance these problems and just avoid avalanche terrain on Sunday.

    (12/18/2020) The debris pile of a large (D2.5) natural avalanche that occurred Thursday night at Mt Hood Meadows in closed and uncontrolled NE facing terrain. The avalanche initiated around 6600' on the rain crust formed 12/9.

Avalanche Discussion

Take this time to observe the power of nature from a safe place as we wait out brutal weather and avalanche conditions through Sunday. And if you must go out, avoid all avalanche terrain as indicated by open valley bottoms or steep paths, trees stripped of branches, or bent over vegetation.

Observers on Friday reported shallow wind slabs had formed, but generally good stability below ~6000'. However, several very large natural avalanches released overnight Thursday at Mt Hood Meadows Ski area in closed NE facing terrain between 6300' and 7500'. These avalanches occurred in wind loaded terrain and had crown heights of several feet up to 6+ feet deep. These very large avalanches slid on the firm rain crust formed on 12/9/20. It is likely that they occurred during a period of intense wind transport on Thursday night.

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.

Regioni coperte