Boletín de aludes

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Strong winds yesterday combined with new snow continued to build wind slabs above 9,000'. Wind slabs were reactive yesterday and these fresh wind slabs may be sensitive to triggering again today. Look for signs of instability, like shooting cracks, wind affected surface textures, before committing to steep slopes. Human triggered avalanches will be possible in steep, wind loaded terrain, especially on sunlit slopes this afternoon.

Avalanche activity on low elevation buttes is unlikely today due to the hard freeze overnight. Continue to consider the impact of sunshine on slopes this afternoon as temperatures rise.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Wind slabs up to a 18" thick were triggered or showed signs of reacitvity yesterday. Most reports indicated that the warm snow and strong winds created slabs on the reactive side of the sensistivity scale rather than touchy.  However, observed buried surface facets in a crust on a SE aspect of Mavericks support the idea that some of the wind slabs, like the one triggered on Wimpy's shown at right, maybe be failing on a layer that is weaker than just new snow particles. Look for this layer and consider if it may turn an othewise firm and apparently stubborn slab into something that you can trigger today. Additionally, you will find fresh wind slabs in the lee of west winds today that were formed by westerly winds. These winds were much more moderate than mid-storm winds making it likely that these slabs will be softer, possibly more sensitive and most likely under a foot thick. Your likley to find both wind slab problems located primarily in the upper elevations were snowfall yesterday was more intense.

    Note that the avalanche problem rose includes solar aspects at mid-elevations due to the potential for heating of wind/storm slabs this afternoon. Monitor temps and solar input onto steep slopes and beware of signs of dampening of snow surfaces. This will make slabs more reactive.

     

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    (3/15/2023)

    This avalanche was triggered from a distance yesterday on Wimpy's in the Tetons.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Lingering beneath a hard slab (and beneath new snow or wind slabs) lies weak layers buried 2-3’ down. The Feb 18th layer is our main concern due to an increase in avalanches in the Wyoming Range(Shepard CreekHoback Peak). The Greys River forecast zone has a diverse snowpack with stark differences between each individual mountain range. The Salt and Snake River Ranges have not seen the uptick in recent avalanche activity or propagating results in stability tests. Our main focus continues to be on the heightened avalanche danger in the Wyoming Range. Increased loading from this  storm will add stress to these weak layers, especially in wind loaded terrain. Reported avalanches have been triggered remotely, and this potential will remain today. Avoid slopes over 30° and understand that large avalanches can be triggered remotely from gentler slopes above, below, or beside steep slopes.

Avalanche Discussion

We have received limited observations from this forecast zone and none since the storm passage yesterday so strong uncertainty exists in snowfall totals and wind slab distribution throughout these ranges.  

Recent avalanche activity has involved wind slabs and persistent slabs that were size 1-2, including some avalanches that were remotely triggered from afar.  Check out the YouTube field report from Blind Bull from Monday the 13th for more on this persistent weak layer concern.

The following recent observation from the Tetons seems likely to be indicative of wind slab problems in this zone:

Buried small facets were observed on a temperature crust beneath the new snow and wind slab yesterday at 9300' on a SE aspect on Maverick. Most areas of wind slab were glued on and generally stubborn though some short, shooting cracks made several reporting parties give a wide berth to larger, unsupported slopes. Snow continued in the afternoon on lighter winds and may make surface clues for the slightly older wind slab challenging. Ski quality was terrible below 8500' even on shady aspects. Bring a knee brace. 

 

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