Boletín de aludes

West Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Sun
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Avalanche danger will be greatest on sun-exposed slopes that become unstable with warming. Move off and away from steep slopes when you start to witness rollerballs or small wet avalanches.  Limited observations above treeline will require you to assess conditions as you ascend.

Problemas de aludes

  • Loose Wet

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

    Clouds and cooler temperatures limited loose wet avalanche activity on Friday. Though we will have a warmer day Saturday, there is uncertainty as to the size and extent of avalanche activity that the sun and rising temperatures will foster. It is for sure that deep dry snow above the treeline will be more susceptible to warming than rain saturated snow at lower elevations. 

    You will probably see signs of instability like rollerballs, pinwheels, or small avalanches on slopes that get direct sun. When these are observed consider limiting your exposure to similar terrain. If you start seeing loose wet avalanches occurring regularly and growing larger then the avalanche danger has increased a notch. In this event avoid being on or under all steep sun-exposed terrain. Loose wet avalanches are unlikely if the snow surface is frozen or partially melted.  

    (3/4/2022)

    Small loose wet avalanche off seracs on the Easton Glacier on Mt. Baker. Southeast aspect at ~7000'.

    Photo: Krissy Fagan

Avalanche Discussion

In addition to wet avalanches, isolated but reactive storm and wind slabs might be found above treeline. Wind transport was noted on the upper reaches of Mt. Baker and other high peaks of the Cascades Friday. With limited observations, it is up to you to assess stability as you gain elevation. Anticipate higher danger in wind loaded or sun warmed terrain and mitigate uncertainty by avoiding steep and unsupported terrain features.

Thursday afternoon a loose wet avalanche cycle to D2 occurred on southerly aspects in West North. Observed avalanches appeared to involve only the top layer of new snow and did not entrain deeper layers of wet snow. Little avalanche activity was noted in Stevens and Snoqualmie Passes the past two days. Weather station data points towards the conclusion that West Central received more rain than snow at below and near treeline elevations during the parade of storms earlier in the week. While areas farther north continued to accumulate new snow and have seen a bigger loose wet cycle, West Central likely experienced peak loose wet activity during prior rain events. The outlier to this is at the highest elevations that have many feet of new snow and could be reactive to a few rounds of strong sun and higher afternoon temperatures.

Surface conditions vary widely from slope to slope with a mix of sun crust, sun-softened snow, extensive avalanche debris, and even settled dry snow masquerading as powder on north aspects near and above treeline.

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