Bollettino valanghe

Mt Hood

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Shallow snow has been transported into wind-loaded and scoured areas throughout the terrain. Wind Slabs remain reactive at upper elevations and Loose Wet avalanches can be triggered as freezing levels skyrocket to 12000 ft. Steer around pockets of shallow chalky or moistening snow on steep slopes approaching 40 degrees.

Problemi valanghivi

  • Wind Slabs

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

    Shallow wind slabs built atop a refreezing upper snowpack. A strong cold frontal passage ended a deluge on Mt. Hood and temperatures plummeted, while light snow showers decreased and winds drifted 2-4" of snow into a patchwork of slabs. These should be easy to identify as they lie atop a stout crust that is exposed in many locations. Until the sun begins to soften the crust, these wind-drifted patches will offer the only reasonable riding conditions. Steering around these patches as they approach 40 degrees and particularly where they might push you into a terrain trap such as a creek or gulley bottom.

     

    Example: Shallow wind slab on a firm bed surface.

  • Loose Wet

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

    Mostly sunny skies and freezing levels skyrocketing to 12000 ft? Believe it or not, this is still January.  The low sun angle should confine wet loose SW-S-SE aspects and to surficial deposits of dry snow that are warming and losing cohesion as the snow warms. As the snow develops a wet or sticky feel, steer around deposits on slopes approaching 40 degrees and avoid exposure to terrain traps which could amplify the consequences of a small avalanche.

    We expect the stout 1/12 crust may soften, but you will be unlikely to break through into wet snow beneath. If you find this crust breaking down and you can sink your boot into wet snow underneath, conditions may be significantly more dangerous than forecast. Move to colder northerly aspects to regain a firm crust and utilize lower angle slopes to reduce the risk of a wet avalanche.

    Example: Old loose wet avalanche activity with more recent loose wet avalanche activity on top.

Avalanche Discussion

Above 8500 ft on Mt. Hood, the 4-5" of water received since Monday translated into massive amounts of snow.  Multiple large avalanche crowns were observed from Mt. Hood Meadows on 1/13  at 8000 ft and above, reminding us that conditions may remain significantly more dangerous above the NWAC forecast area.

By Thursday morning we're just over 24 hours out from a huge amount of water hitting the snowpack and undoubtedly water is still moving under the crust. If snow conditions are not in line with the forecast, it may be that you are in terrain where warmer temperatures are breaking down the crust. If you find deep wet snow you sink into, dial back your terrain selection to exclude slopes steeper than 30 degrees.

Non-avalanche hazards will be significant on Thursday:

  • Firm and icy slopes have been reported in other forecast zones. Make sure you can self-arrest on the slopes you travel and consider bringing tools if you travel on steeper slopes.
  • Creeks may be blown out, difficult to cross, and have high and fast-moving running water.
  • Trailheads may be difficult to access due to downed trees, debris, and potentially flooding.

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