Boletín de aludes

Intermountain

Valdez Avalanche Center
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Peligro de aludes

Alta montaña
2 · Moderado
Límite del bosque
3 · Notable
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 7 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The avalanche danger remains Considerable at Mid elevations and Moderate at upper elevations.  Human triggered avalanches 2-3 feet deep are likely between 2500-3500 feet elevation.  Larger avalanches up to 4 feet in depth will be more difficult to trigger, but remain possible above 3500 feet.  Even though a weak snowpack exists, signs of instability are unlikely.  

A strong rain crust exists below 2500 feet making human triggered avalanches unlikely.

Public avalanche forecasts are issued Wednesday-Sunday at 8 am. 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–2.5

    Weak snow exists near the ground at all elevations, but it is most pronounced in the 2,500–3,500’ band. This mid-elevation zone is our #1 area of concern and is capable of producing 2–3’ deep avalanches—large enough to injure, bury, or kill a person. Over the last week, the slab above this weak layer has been settling and gaining strength, but the weak layer beneath has not strengthened at the same rate.

    The best travel advice for this problem is to pay close attention to when you enter this elevation band and make a conscious effort to choose simple terrain under 30°. If you decide to travel in steeper mid-elevation terrain, expose only one person at a time to avalanche terrain, keep eyes on your partners, maintain clear communication, and avoid terrain traps.

    Because these slabs are deep and dense, you may not see obvious signs of instability even when dangerous conditions exist.

    Deep crown from a natural avalanche that failed in the mid elevation band .  

    Photo: Paul Ramseth

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3

    Above 3,500’, the base of the snowpack is a variable patchwork of old wind slabs sitting over facets (weak, sugary snow). These old wind slabs remain strong and continue to bridge the weak snow near the ground. Observations still show a generally stronger snowpack at upper elevations than at mid elevations, where the basal weak layer is more developed.

    Our concern is that a person could trigger a deep, hard slab avalanche where the wind slab is thinner or absent and the weak layer is closer to the surface. This problem is difficult to assess because these thinner “trigger points” can be small and hard to identify. You can reduce your risk by avoiding large, steep alpine faces with thin, rocky areas. You can avoid this problem by choosing terrain under 30°.

    This problem is expected to have a higher sensitivity and likelihood in the Continental zone.

     

     

    (1/23/2026)

    Large connected natural hard slab avalanche associated with our deep persistent weak layer. Mt Dimond north face

    Photo: Gareth Brown

Avalanche Discussion

Avalanche activity in the last 72 hours: None observed or reported

Forecast Discussion

Weak snow that formed in December remains our main concern.  This situation can be frustrating as the upper snowpack settles and gains strength, but weak snow remains near the ground.  Direct feedback such as signs of instability are now unlikely due to the depth and density of the slab, making it increasingly challenging for users to stay diligent in their terrain choices.  

This scenario is one of the more dangerous setups we have seen on Thompson Pass in recent years.  The snowpack is difficult to assess and the structure is variable, especially above 3000'.  The likelihood of triggering an avalanche is slowly decreasing, but the consequences would be severe as slabs above weak snow are dense and deep.

Safer conditions exist below 2500', where a strong rain crust exists at the surface making human triggered avalanches unlikely.

 For more information regarding our snowpack, see our Season summary, Observations, and avalanche activity sections. 

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