Bollettino valanghe

Continental

Valdez Avalanche Center
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Pericolo valanghe

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

In sintesi

The avalanche hazard is Moderate at all elevations.  Human triggered avalanches are possible up to 2 feet in depth in specific areas.  Slopes that have been loaded by recent north wind remain a concern.  Natural avalanches are unlikely.

Problemi valanghivi

  • Wind Slabs

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

    North winds have meaningfully decreased over the last 24 hours with calm conditions observed at most of our weather stations as of 6am. This will allow for wind slabs to stiffen and slowly gain strength.  This process will take longer than what is typical since wind slabs overlie faceted snow in some locations.  The depth of these slabs will be less than 2 feet in the intermountain and continental zone and up to 3 feet for the Maritime zone.

    Several D1-D2 natural avalanches were observed and reported in the intermountain and continental zone yesterday.  This activity reinforces the idea that faceted snow exists below wind slabs in many locations.  As slabs stiffen avalanches will become more difficult to trigger, but may have wider propagations once initiated.  

    Check for the presence of wind loaded snow.  Use small incosequential test slopes to check the sensitivity of slabs in the area you choose to travel.  Checking for the presence of facets beneath slabs is recommended if traveling in consequential terrain.   

    The hazard will be lower in areas protected from the latest moderate outflow event.  Seek out sheltered snow for better riding quality and stabiity.

    Test slope failure at Benzene Alley on 1/9.

    Photo: Gareth Brown

  • Glide Cracks

    • Tutte le quote
    Probabilità
    Unlikely
    Dimensione
    2.5–3

     Glide avalanches are a strange beast that act differntly than other avalanche problems.  Full depth failure can occur independent of snowpack stability.  Or in other words, they can release even when a stable snowpack is in place.

    Since it is not possible to time their sensitivity the only way to mitigate this hazard is by avoidance.  First identify where glide cracks exist and avoid spending time beneath them.  Glide cracks are easy to identify.  They look like crevasses, but exist in non glaciated terrain.

    These do not produce small avalanches,  but rather failure will include the entire snowpack.  

    Glide release on Town mountain

    Photo: Rich Lofton

Avalanche Discussion

The main avalanche concern remains slopes loaded by recent wind.  Keeep in mind that facets formed during the last 2 weeks of mostly clear and cold weather may allow for instabilities to persist longer than what is typical.   

Good stability has been reported and observed in areas unaffected by recent wind.  The 1/7 snowfall was light for the Intermountain and continental zone with 2-6 inches observed.  The facets mentioned above have recently been buried by new snow, although a sufficient slab has not yet developed above this weak layer in areas unaffected by wind.  The Maritime zone received higher snowfall amounts although this snow was quite dry and only involved .35 inches of water, which is still not enough to overwhelm this weak layer without the additional weight and cohesion of wind redistribution.

Light snowfall is in our mid range forecast which will slowly add stress to the 1/7 buried surface hoar.  It is possible this layer will become a problem in the future.

Glide cracks have been observed in all three forecast zones.  Avoid travelling beneath these as full depth avalanches can release unexpectedly.

Valdez season snowfall: 160 inches

Valdez January snowfall: 15 inches

Valdez height of snowpack: 62 inches

Thompson Pass snowfall data is currently unavalable

46 mile height of snowpack: 65 inches

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