Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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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 still trigger large slab from the last storm. Continue to avoid steep, wind-loaded slopes, particularly below heavily corniced ridgelines.  Several layers of buried surface hoar continue to warrant travel on lower angle, supported slopes near treeline and below.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    Strong to extreme winds peaked Tuesday night and generated a natural avalanche cycle of large, firm slabs.   Wind slabs up to size 2.5 ran on the SW side of Mt. Hood, with NW winds moving snow on the upper mountain. Another observer found size 2 (large) natural avalanches on SE aspects in the Timberline area with multiple step-downs indicating the presence of some weaker interfaces (possibly buried 12/8 or 12/18) and continued prospects for more widely propagating avalanches. Mt. Hood Meadows Pro Patrol also triggered a large avalanche (2-4 ft crown) with explosives on a NE aspect on Wednesday. Slabs may be slow to heal during this cold air outbreak and may be firmer and break more widely than you expect. Continue to give heavily wind-loaded slopes a wide margin for safety, particularly under heavily corniced ridges. Hollow-sounding snow, whumphs or shooting cracks serve as a strong reminder of the elevated hazard. Travel safely on ridgelines, windward slopes, and those less than 35 degrees. Don't let the shifting wind directions over the next 24 hours throw you off the scent of the older, larger and more dangerous slabs.

     

    (12/21/2022)

    Terrain in the lee of large cornices may harbor slabs primed for human trigger on Thursday. Photo depicts crown and debris of a large natural avalanche immediately east of the Timberline ski area boundary. ~6,200’, SE aspect. 

    Photo: Ryan Matz

  • Persistent Slabs

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

    13" of recent snow arrived with this last storm and may rest on a new layer of buried surface hoar (buried 12/18). We have limited information about this interface as it does not appear to be widespread, but we think it may have been preserved in some wind-sheltered areas on N and NE aspects. It shows up in a very pronounced grey stripe in a test pit near Mitchell Creek on 12/20.

    The older 12/8 buried surface hoar also showed up clearly in the aforementioned test pit from Mitchell creek, reminding us that this widespread layer remains in the upper 2' of the snowpack. This layer has the potential to produce isolated large avalanches. Avalanches triggered on the 12/18 weak interface could step down to this layer to produce avalanches that could ruin your day.

    Given the complex and layered nature of the current snowpack, keep your terrain choices simple, choosing smaller, supported terrain features, thickly treed slopes, and larger open slopes less than 30.

    (12/20/2022)

    12/8 PWL and new layer of buried surface hoar 12/18.

    Public Field Report: Mitchell Creek, Mt Hood Meadows

    Photo: Dave Watson

Avalanche Discussion

Cold temperatures remain a concern and heighten the risk of any incident in the backcountry on Thursday. Travel with extra layers.

Snow may start to fall late in the day, but Thursday will be the last day before warmer and wetter conditions move into the area for the weekend.  Share an observation with us and the local community. 

Regioni coperte