Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

The spring shed is underway, and a multi-day warming trend will peak on Sunday. Wet avalanches, cornice fall, and snow shed from rocks is expected to increase substantially as the daytime warms up. Finish your day early, and avoid going on, or underneath steep slopes that are in direct sun. 

Problemas de aludes

  • Loose Wet

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

    The warmup is on, and wet loose avalanches should be expected over the next few days. Avalanche danger will be lowest first thing in the morning while the surface crust is still frozen and supportable, but may quickly rise with direct sun and daytime warming. Pay attention to how supportable the surface is, looking for wet, punchy snow, rollerballs, and wet avalanche activity. Be ready to finish early, and avoid traveling on, or underneath large steep slopes in the sun.

    Loose wet activity may increase substantially in the afternoon, and slides could become large in larger terrain features near and above treeline. Slides may also become larger if they gouge into deeper layers.  Consider your terrain choice, and be ready to move off of large, steep features by the heat of the day. Even a small slide could knock you off your feet, carry you into trees, rocks, over cliffs. Take a minute or two to observe for overhead hazards or recent activity before entering complex terrain.

    Chances for large avalanches are increasing as we go through this warming trend. These could be glide avalanches, wet slabs, or massive cornice failure. Keep your senses tuned into the snow and look for signs of deteriorating snow stability. If you see large avalanches run, then conditions are dangerous so make adjustments accordingly. There's also potential for wet slabs. These are most likely on steep, rocky and unsupported slopes that receive direct sun, and could be triggered by rollers or loose wet sluffs. The best advice is to move off of steep slopes before the snowpack becomes punchy and unsupportable. 

    (4/23/2022)

    Long running wet loose avalanches were observed on southeast aspects above Lake Ethel.

    Photo: Joe Dellaporta

  • Cornices

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

    With the very warm temperatures, cornices may begin to sag, and fall. Some cornices are very large, and could be dangerous in their own right. Large cornices could also impact slopes below and entrain into even larger avalanches. With the very warm temperatures, snow has also been shedding from rocks.

    As a general rule, try to avoid large, complex terrain features that could harbor cornices and rocky cliffs with snow pillows. Consider what is beneath some slopes with large cornices, and steer clear from their runout zones. 

    Cornice failure and glide avalanche example photo.

    Photo: Lee Lazzara

Avalanche Discussion

Sunday marks the peak of a gradual warming trend following a couple weeks of below normal temperatures with lots of snow in April. Over the last week and a half, 2-4 feet of snow has accumulated in the East Central. This alone is a good reason to be very cautious in the mountains on Sunday. Avalanche activity is expected to increase in frequency and perhaps size as well.

On Saturday I observed a recent natural glide avalanche off some rocks in upper Tumwater Canyon. Another observer found some long running loose wet avalanches on southeast aspects above Lake Ethel in the Chiwaukum Range. He also found dry snow with shooting cracks in an isolated wind slab. Point releases were reported from sunny slopes near Mission Ridge on Saturday morning as well. On Friday there were medium sized wet loose slides from very steep south facing couloirs on McClellan Peak. I also observed a few small loose wet slides on west facing slopes near treeline off Table Mountain near Diamond Head, and in Icicle Creek drainage. The surface crust was supportable and made for easy travel in the morning, but melted down and the snow became punchy later, especially on East facing slopes. I was able to initiate small loose wet slides below treeline on very steep slopes. On Thursday, Mission Ridge reported 7" of new snow in their upper basin, and areas near the crest picked up slightly less amounts. Some loose wet avalanches were observed there, and in some steeper chutes of Tumwater Canyon by mid afternoon that day(see photo below).

This is NWAC’s last daily avalanche forecast for the 2021-2022 winter season. Mt Weather Forecasts will continue until May 1. Make sure to check our Spring Avalanche Statement for information and travel advice. NWAC will continue to track snow and weather conditions. Large storms and/or widespread avalanche cycles may cause us to issue special avalanche bulletins, avalanche warnings, or other spring statements to keep you informed. You can help your backcountry community by continuing to submit observations of avalanches, snow, and pertinent weather to our site. Have a fun and safe spring recreating in the mountains!

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