Bollettino valanghe

Intermountain

Valdez Avalanche Center
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2 · Moderato
Limite del bosco
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Sotto il limite
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In sintesi

The avalanche hazard is Moderate at all elevations.  Human triggered avalanches up to 1 foot in depth are possible.  Natural avalanches are unlikely.  Multiple avalanche problems exist. Read the avalanche problems description below for more details.

 

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

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    A dangerous snowpack structure exists in all three forecast zones at and below 3000'. A stout rain crust forms an excellent bed surface, and buried surface hoar sits above it. What varies by zone is the slab on top.

    The Maritime zone is the primary concern today because the snow above the weak layer is deep and cohesive enough to act as a slab. In the Intermountain zone, including Thompson Pass, we’ve found roughly 10–12 inches of new snow above the weak layer, but the snow remains relatively low-density and uncohesive, making triggering less likely than in the Maritime zone. In the Continental zone, 4–8 inches of new snow covers the weak layer and is not yet sufficient to create a major problem.

    This layer is not expected to heal quickly. As the snow above it settles, stiffens, and deepens with additional snowfall and wind redistribution, sensitivity is expected to increase. Because the weak layer is still relatively close to the surface, signs of instability—shooting cracks and collapsing—may be present where triggering is likely. Identifying where this problem exists can be straightforward: if you can probe a firm rain crust beneath the new snow, assume buried surface hoar is present above it. Avoid steep or complex terrain below 3000' where you find a cohesive slab at the surface, especially in the Maritime zone.

    Wind Slab: North winds increased overnight on Thompson Pass. Watch for small, fresh wind slabs in specific wind-loaded terrain features. Be especially cautious if you encounter wind slab formation below 3000', where it may combine with or add stress to the buried surface hoar problem.

    1/26 BSH found under 1 foot of new snow. Girls/ S/ 2300'/2mm grid

    Photo: Gareth Brown

  • Deep Persistent Slabs

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

    Weak snow near the ground exists at all elevations and is deeply buried in most locations. In many areas, weak faceted snow is now bridged by stronger, stiffer layers in the middle of the snowpack. As this problem gets deeper, it becomes harder to trigger and is unlikely to produce obvious red flags like cracking or collapsing. Expect a stubborn, unreactive deep slab in most locations—this is a low-likelihood but high-consequence setup.

    The most likely trigger points are thinner areas of the snowpack, especially steep, rocky terrain where weak layers are closer to the surface. A rider may be able to stress the basal weak snow in these shallow spots, and a small trigger could step down or propagate into deeper, thicker parts of the pack, producing a large and destructive avalanche. The best way to manage this problem is to avoid steep, rocky features and other shallow-snow areas where the snowpack is thin and variable.

    In the Continental zone, the hazard will remain Considerable, where the snowpack is thinner, weaker, and more easily affected by human triggers.

    (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

Forecast Discussion

Persistent weak layers have been a main concern for much of the season. These problems can linger for weeks to months, become dormant, and then reactivate with additional loading from snowfall, wind, or rain. We will continue tracking both the recently buried surface hoar and the older weak snow near the ground (facets and depth hoar).

The buried surface hoar has been most reactive in the Maritime zone and relatively quiet in the Intermountain and Continental zones so far. This may change as the slab above the weak layer settles, stiffens, and deepens with time and additional snowfall—making triggers more likely and allowing fractures to propagate farther.

Our deep persistent weak layers remain a low-likelihood, high-consequence concern. The deeper snowpack at upper elevations has been slowly gaining strength, but thin and rocky areas remain potential trigger points where a person could still stress weak snow near the ground. Uncertainty remains high at upper elevations due to variable snowpack structure. Triggering may be difficult, but any avalanche that fails near the ground could be large and destructive.

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

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