Bollettino valanghe

Summit Lake

Chugach National Forest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

There is a chance a person could trigger an avalanche 1 to 2’ deep on a layer of buried surface hoar above 2,000. Be wary of steep slopes even if you do not see red flags. The safest option is to stick to low angle terrain and avoid being underneath steep slopes. Look out for fresh wind slabs in upper elevations and wet loose avalanches on slopes in the sun.

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SPECIAL ANNOUNCEMENT

Avalanche Accident:  We are deeply saddened to report that on Saturday a snowmachiner passed away in an avalanche on the backside of Seattle Ridge in Turnagain Pass. Our preliminary report can be found here and we will provide a full report as soon as we are able.

Problemi valanghivi

  • Wind Slabs

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

    Overnight windsfrom the east blew snow into fresh winds slabs up to 1’ deep. These will be more likely at upper elevations, below ridges, rollovers and in cross loaded gullies. Look out for blowing snow which is an indicator fresh wind slabs are forming. Clues like shooting cracks or snow that becomes stiff underneath you mean you are likely traveling on a wind slab. 

    Loose snow avalanches may be easy to trigger on steep solar aspects (east, south, west). These will become more likely if the sun has a chance to poke through the clouds and temperatures warm up quickly. These may release from a point and get larger as they carry more snow down the slope or trigger a small slab avalanche. Seek shadier slopes if you find yourself in the sun and see rollerballs releasing. Worst case scenario, one of these avalanches trigger a large avalanche on a buried weak layer.

    Limit time spent under cornices and giving them a lot of room on ridges. Look out for glide cracks above you and limit time spent under them. They can release spontaneously into large glide avalanches. 

  • Persistent Slabs

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

    There is a chance a person could trigger an avalanche around 1 to 2’ deep on the same layer of buried surface hoar that is responsible for many human triggered avalanches in Turnagain Pass. We heard reports of whumpfing/collapses and shooting cracks on Raven's Ridge and John Mtn. These are red flags telling us that these slopes would have produced an avalanche if it was steep enough to slide. The point is the problem does exist and could trigger an avalanche deep enough to bury a person.

    What we are learning from the Turnagain Pass avalanches is that if there is surface hoar buried under a slab it has the potential to slide. This layer may give stable results in snow tests or be impossible to find on a slope. Look out for whumpfing/collapsing and shooting cracks and be aware that these clues may not be present. Choosing smaller steep slopes that fan out and do not have terrain traps like creeks or gullies in them where snow could pile up are smart options. The safest way to avoid this problem is sticking to lower angle terrain.

Regioni coperte