Bollettino valanghe

Snake River Range

Bridger-Teton Avalanche Center
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Pericolo valanghe

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

In sintesi

The chance continues to trigger avalanches involving old snow layers at the mid and upper elevations. They could be triggered while on, near or under steep avalanche terrain. This instability is best avoided by conservative terrain choices and thorough snowpack evaluation.   Newly formed wind slabs could also be triggered near ridge crests where fresh snow was deposited overnight. 

Yesterday one skier died and another was injured in an avalanche that occurred near Togwotee Pass. TCSAR responded to the accident. The avalanche center staff sends our sincere condolences to the family, friends, and rescuers involved in this tragic event. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–2.5

    Weak snow layers that were buried in December continue to pose a threat to backcountry skiers and riders. Although it is nearly a week since any known avalanche activity has occurred involving these layers in the Teton Range or Snake River ranges, the chance of triggering a large hard slab avalanche with depths of 2 to 4 feet cannot be ruled out.  Whoomphing or cracking are strong signs that this hazard is present although in many areas the recent storm snow will feel supportive and fail to indicate the existing weakness. If venturing from conservative terrain, snowpack evaluation is essential in avoiding this hazard. 

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Newly formed wind slabs up to eighteen inches in depth could be triggered on steep leeward slopes. These slabs will be larger and more sensitive in wind loaded areas that received higher 24 hour snowfall amounts which varied by specific location. Watch for and avoid terrain that shows obvious signs of wind loading. Remember that even small slides can carry consequences in steep rocky areas or in places that can carry someone into a terrain trap. 

Avalanche Discussion

This is a snowpack that demands respect. In the Snake River Range it requires diligence to remember that although most slopes have become stable, the persistent weak layer exists and although unlikely to trigger, an event could result in death or injury. Never make the quick determination that Moderate (Level 2) is a green light to hit any terrain. It simply means that slabs are more stubborn to initiate and/or that the weakness is not widely distributed.  Slab failure on a slope with the lingering hazard may require a weak spot on a slope to be impacted, even after tracked, or a large load. Follow safe practices such as only exposing one person at time to an avalanche path, evaluating the snowpack, and communicating with your group. Remember that less than a week ago a party of 4 triggered a large avalanche from below resulting in 2 burials that were fortunately rescued by the remaining party members. 

Although little is currently known about the accident at Togwotee yesterday, it is believed that the group of 4 triggered a large slide that initiated well above them as they travelled through steep terrain.  As is typical, the snowpack at Togwotee is under wrought with very weak snow and in this location the slab over it was significant and allowed for the group to initiate a collapse that propagated up into the steeper terrain above them where the slab released. Poor visibility may have also played a part. Updated information can be found here.

 

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