Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 8 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

If you're taking your toys out to play on Thursday, you better watch out for wind-loaded features where triggering an avalanche is more likely.  With the wind coming from all directions this week, they may be found on a variety of aspects or further downhill than you're used to. Avalanches may be easier to trigger in shallow, rocky areas of the zone.

Problemas de aludes

  • Wind Slabs

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

    We're expecting another windy day on Thursday, so you'll need to continue managing wind slabs in leeward terrain. The wind direction is expected to shift multiple times throughout the forecast period, potentially leading to shallow slabs forming on a variety of aspects. With only a few inches of new snow expected and several windy days already this week, the question becomes - how much snow is left to blow around? Our hunch is that there's still plenty, particularly up high.

    Look out for sensitive wind slabs near rocky terrain such as the base of cliffs, in confined chutes, or on convex features. Textured surfaces, large pillow-like drifts, or firm, hollow-feeling snow are all indications that the snow may be unstable and you should head for sheltered, lower-angled terrain.

    In some locations, interstorm layers or snow sitting above the 12/18 crust may result in more sensitive or surprising slab avalanches. Be leery of steep slopes that are not only wind-loaded but are also generally rocky and thin. These seem to be the spots where recent avalanches have been easier to trigger. 

    (12/23/2025)

    A human-triggered slab avalanche at Crystal Mountain Resort. It failed down to the 12/18 crust, and you can see a lot of rocks and trees sticking out.

    Photo: Crystal Mountain Pro Patrol

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Down low, the snow got wet on Wednesday and may do so again on Thursday. This time, however, a surface crust will likely have formed overnight, and less precipitation is forecast. But we're still expecting rising freezing levels and drippy conditions, so there remains a possibility of wet avalanches.

    Although less likely than on Wednesday, any wet slide should behave similarly. It will start at a point, such as near rocks or trees, and then fan out as it moves downhill. Don't let one push you into a terrain trap or into the many exposed natural hazards that still exist in the mountains right now.

    (12/24/2025)

    Natural avalanche activity in Lakes Basin. Both wet and dry avalanches were observed on 12/24. 

    Photo: Andy Harrington

Avalanche Discussion

Happy Holidays from all of us here at NWAC! Christmas Day should be very similar to Wednesday, but with slightly less impactful weather. Additionally, the snowpack has already had a day to become accustomed to the current weather pattern after temperatures crept up the mountainside and winds howled from various directions on Wednesday. Thus, a slight reduction in avalanche hazard is warranted for Thursday. At upper elevations, dangerous conditions will persist where deeper and drier snow is exposed to stronger winds.

This past week has been characterized by a steady stream of snow-producing storms that have slowly increased the depth of our early-season snowpack. All of this storm snow sits above a stout melt-freeze crust (12/18). The depth of this interface varies around the zone, but it can be over 2 feet below the surface in protected areas and even deeper in wind-loaded spots. However, areas where it's closer to the surface may pose the biggest issue.

Near Crystal Mountain, we've had numerous reported avalanches failing down to this interface in recent days. NWAC forecasters visited the Crystal area on Wednesday to look for problems at the 12/18, and their tests did not produce any concerning results. However, please don't ignore the red flag sign of instability - recent avalanches. We've had at least one a day all week, so store that in the back of your mind. Additionally, NWAC forecasters found an interstorm layer of graupel, 4-6 inches below the surface. This layer was responsible for a widespread natural avalanche cycle during today's storm. Down low, in both the Crystal and White Pass areas, moist snow and wet loose activity were reported.

Lastly, it wasn't that long ago that we had major atmospheric river events totally saturate our soil, weakening the roots of many trees. We've already survived one round of wind, but another is on our doorstep. Be cautious when traveling in the forest - trees may be more prone to falling than usual, and snow shedding as "tree bombs" could fall without warning. Add it to the list of early-season hazards you'll need to manage, along with open creeks, downed trees, and exposed rocks.

State and local resources are working diligently to reduce the impacts of destructive storms that occurred earlier this month. We can help by respecting affected communities, complying with road closures, and adhering to ski area uphill travel policies.

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