Bollettino valanghe

Tetons

Bridger-Teton Avalanche Center
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Pericolo valanghe

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

In sintesi

Dangerous avalanche conditions exist in steep, wind loaded terrain at the upper elevations of the Tetons. Human triggered avalanches 1-3 feet deep are likely in these locations. In addition, rocky and very steep unsupported slopes contain deeply buried weak layers that have just been stressed by a significant load. Careful snowpack evaluation and conservative terrain selection are essential in these locations.

Problemi valanghivi

  • Wind Slabs

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

    The upper elevations of the Tetons received about 40 inches of snow from March 1st-3rd. This snowfall was accompanied by strong and sustained winds out of the southwest. Wind slabs with depths ranging from 1-3 feet have formed in leeward terrain at the upper elevations. These slabs are slowly stabilizing, but triggering one remains likely today in steep, exposed terrain in the upper elevations. Be on the lookout for evidence of wind drifted snow in these areas such as pillows or textured surfaces. Probing or digging to identify hardness changes (hard over soft) are great ways to identify these slabs. Careful snowpack evaluation is essential, however, giving steep, wind loaded terrain a wide margin is also an effective strategy today.

    Human triggered wind slabs are likely today in terrain that looks like this.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Weak snow buried over 5 feet deep persists in the snowpack. These weak layers have just been stressed by nearly 5 inches of water in three days. This is a tremendous amount of weight in a short period of time. A lack of large avalanche observations from yesterday would indicate that the weak layers weathered the loading event fairly well. Despite this, the recent extreme loading requires vigilance. Terrain where this problem is most hazardous includes very steep, hanging snowfields above cliffs and rocky or notably shallow slopes. Keep in mind that a large wind slab release or cornice fall has the potential to trigger one of these very large avalanches.

    "Very steep, rocky, and unsupported terrain"

Avalanche Discussion

We are two days out from the largest and most rapid loading event of the season. Nearly 4 feet of snow containing about 5 inches of water fell in the upper elevations of the Tetons in 2 days. Ten day cumulative water totals are sitting at around 6” of SWE. Observations from yesterday indicate that the storm snow is stabilizing on many slopes and very few avalanches were observed. However, the most recent storm was an abnormal weather event. Consequently, backcountry travel today may require an abnormal amount of vigilance for this time of year. Spring is coming and conditions will stabilize quicker than they would in January. We are just too close to the loading event to confidently trust the snowpack in certain areas. Careful evaluation of the snowpack, smart terrain selection, and maintaining an extra margin of safety to account for surprises is a good idea today.

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