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 hazard is Considerable at mid elevations, and Moderate at upper elevations.  A weak snowpack that is overloaded by last week's snowfall exists.  Human triggered avalanches up to 3 feet in depth remain likely in specific areas.  The hazard is lower at upper elevations, however dangerous avalanches remain possible for a person to trigger.

It is unlikely to trigger an avalanche at low elevations where a stout rain crust exists.

Special Announcement:  DOT will be using explosives for avalanche mitigation from mile post 30- 35.  Do not travel in these areas.

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
    2–3

    An unusually fragile snowpack exists in the mid elevation band that is overloaded by last week's snowfall.  Having a clear picture of where this dangerous setup is will be important today and into the future, as the weak snow that exists in mid elevations at the base of the snowpack will not heal quickly.

    This poor setup exists on all aspects at elevations above the most recently formed rain crust (1/15) and up to 3500'.  This is a pretty narrow window where the most dangerous snow can be affected.  Users should be aware of where this elevation band is on their route and choose terrain that is less than 30° and only expose one person to a slope at a time.  The slab that overlies the weak snow is deep enough and dense enough that signs of instability will probably not be present.  

    The majority of recent natural avalanche activity that can be seen is a direct result of this weak snow.  Many of these slopes failed mid storm and have been reloaded, and could potentially fail again.  Terrain management is the best way to avoid this problem.  

    For a better understanding of how this weak snow formed and why the trigger zone is in such a narrow band refer to the forecast discussion section.

    (1/21/2026)

    Natural avalanche activity within the mid elevation band

    Photo: Gareth Brown

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2.5–3.5

    Above 3500' the snowpack structure is very different.  We are still finding facets (weak) snow near the bottom of the snowpack in some locations, but strength is higher, facets are denser, stability tests are not yielding concerning results and a patchwork of old hard wind slabs continue to bridge weak snow at the bottom.  Temperatures are above freezing at upper elevation and have been so for 4 days at Nicks wx station.  This will continue to cause storm slabs to consolidate, which may increase sensitivity.

    The snowpack at upper elevations may be better than what is found in the mid elevation band, but it is far from good.  It remains possible for users to trigger a hard slab avalanche, especially from thinner areas of the snowpack, such as rock bands and high points of terrain.  Low-lying concave pieces of terrain where the snowpack is deeper will be safer.  

    The base of the snowpack has a significant amount of spatial variability making assessment very challenging.  Snowpits can be misleading as the snow structure can be vastly different just a few feet away.   Using an avalanche probe in multiple locations along your route can be a good tool to give an idea of snowpack structure.  Increase your margin of safety by travelling one at a time through avalanche prone slopes, avoid steep rocky terrain and terrain traps.

    The Continental zone holds more of a concern for human triggered avalanches at upper elevations for multiple reasons.  First is that this climate zone received less wind in December, allowing for a more unconsolidated snowpack to exist that could facet more efficiently.  Secondly, temperatures are colder in this region which also promotes more aggressive faceting.  And third, this region received less snowfall with the last storm creating a situation where some weak areas of snowpack were not loaded enough to naturally avalanche but could still be triggered by a person. The hazard is Considerable at upper elevations in the continental zone.

    (12/24/2025)

    Developed facets beneath knife hard wind slab @3200' Crudbusters

    Photo: Gareth Brown

Avalanche Discussion

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

Forecast Discussion:

Well, if you read the above section and are left feeling confused, you are not alone!  The snowpack is very complicated this year with mutiple probelms and a high degree of spatial variability.  This is not a typical Thompson Pass snowpack and should be treated with respect.  The avalanche problems we are dealing with carry high consequences; we are not talking about small avalanches that you can just ski away from. These are slides that would be difficult to escape and can kill you.

Upper elevations is where we have the highest uncertainty.  Uncertainty is lower in the mid elevation band, which is good because that is where the snowpack is the weakest.  Weak snow in the mid elevation band was created by the formation of the 12/1 rain crust.  This crust prevented the hurricane force winds of December from gouging any deeper than this crust.  Higher up the snowpack became stripped, variable and very dense.  The snow beneath the crust was not compacted by wind, the lower density allowed for significant faceting to occur down to the ground as temperatures remained well below normal for a month.  The most recent storm created significant avalanche activity failing at the 12/1 rain crust.  It is now diffiicult to identify the 12/1 crust as it has been crushed by the weight of the new snow, however the faceted snow beneath the crust remains and will continue to be fragile for the foreseeable future.  The most recent storm not only brought heavy snow to upper elevation but also a significant amount of rain at lower elevations.  Rain line has been observed to exist from 2500-3200' depending on location.  This has narrowed the window were the mid elevation facets are likely for a person to trigger.  The 1/15 rain crust is strong and supportable making human triggered avalanches unlikely where it exists for the time being.  So that leaves us with a range from 2500-3500' where the highest concern exists this range could be smaller or larger dependant upon the existence of the 1/15 rain crust and the existence of the mid elevation facets.  The mid elevation facets can easily be identified by simple ski pole probing.  Clear as mud?

 

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

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