Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Warm temperatures and a strong April sun will try to cause the snow to become wet and unstable Thursday. You’ll need to pay attention to the surface and how it changes throughout the day. If you find wet, sticky, or punchy snow seek our more frozen or lower angled terrain to avoid the hazard.

Problemas de aludes

  • Loose Wet

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

    Competing weather factors will attempt to influence the surface snow Thursday. Warm temperatures and sunshine will struggle against a cooling breeze and potential clouds. When the warm sunny conditions win, you will notice the snow surface becoming wet and sticky. If you find you sink in past your ankle, experience punchy snow, or see new rollerballs it’s time to go somewhere else. Seek out more frozen or lower angled slopes to avoid the unstable wet snow. The overnight refreeze will significantly impact how quickly the danger rises. If you find very firm and strong snow in the morning, this may help limit the avalanche hazard. If you encounter a thin, weak, or breakable crust, expect the danger to rise rapidly. Unstable snow should form first on easterly aspects before moving to other slopes. With this weather pattern, you may see wet snow spread to even more shaded features. Only high shaded slopes should retain cold dry snow during this warm-up. 

    We anticipate the cooling breeze and patchy clouds to help confine the unstable snow to steep rocky features. However, if a poor refreeze combines with warm temperatures and sunny skies, more dangerous conditions could develop. If you see numerous small loose slides or find much larger avalanches that entrained significant amounts of snow, dial it back and give avalanche paths a wide berth.

    (3/28/2021) Loose wet avalanches like these on the NE aspect of the Castle (Tattoosh Range, Mt Rainier) show the power of the sun to reach all but the due north faces in the springtime. 6300', NE, The Castle.

Avalanche Discussion

You should experience the lowest avalanche hazard in the morning before the surface weakens. As the day progresses the avalanche danger may peak on different slopes at different times. You’ll need to constantly watch the snow surface to recognize these changing conditions. Locations near the volcanoes could develop the greatest danger. These sites saw the highest snow totals during the recent storm and may receive the weakest refreeze due to warmer overnight temperatures. If you travel near Paradise, Mt St Helens or Mt Adams choose routes with plenty of options to adapt to rapidly changing conditions. 

A recent storm Sunday/Monday accumulated 10-15” of snow around the West-South zone. Very strong and sustained winds accompanying the storm formed a variety of surfaces including scoured crusts, deep drifts, and wind-packed snow. These firm surfaces should help limit the potential for loose wet avalanches at upper elevations and on exposed features. In more sheltered sites, the recent snow sits above a firm crust (3/28). Avalanches occurring on this smooth surface may run far and fast. 

Large cornices loom on some ridgelines around the region. Warm periods such as this always make us nervous about them falling down. Choose routes that limit the time you need to spend near or below these looming waves of snow. Collapsing cornices and loose slides could act as a trigger for slabs on slopes below. Despite the spring-like weather, the snowpack has not fully undergone its transition. Several layers remain that might produce isolated large avalanches. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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