Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

It was hot on Friday and it's going to be hotter on Saturday, with snow losing its crust very quickly in the morning. You could trigger a wet avalanche if you're sinking more than a few inches into snow on steep slopes. 'Tis the season for shed-style avalanches, so this is a good time to avoid travel beneath cornices, glide cracks, and patches of snow perched on steep rocks.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    If you have an early start there may still be enough of a crust at the snow surface to hold avalanche activity at bay for a period. It won't take long for avalanches to begin. When you start noticing the snow softening and any snow sliding, it's time to retreat from areas where you might trigger a slide or where slides could run down onto you. 

    There are two separate wet avalanches to be aware of on Saturday. The first involves the surface snow over the Early April Crust. Snow will become wet and weak as things heat up and crusts break down. You’re most likely to trigger a loose avalanche where you find wet snow deeper than your ankle. These slides will probably remain small, but could still easily carry you over a cliff or into a creek. In the past few days, many small natural and human-triggered avalanches involved this recent snow. However, more could still come down, particularly on the more shady aspects where this snow is taking longer to transition to melt forms. 

    The other process involves the spring snowpack transition. These slides are less likely but more consequential. They might happen before the day warms up much as well. They involve glides, cornices, wet slabs, and gouging wet loose avalanches. These shed-style events are very hard to predict and can occur with very little warning. They’re most common in big rocky terrain regardless of aspect and elevation. Look for routes that help limit your exposure to overhead hazards. If you start seeing larger slides, get away from similar terrain.

    (1/29/2024)

    Example photo: Wet avalanches on Cave Ridge from earlier this year but similar to what you might see on Saturday. Don't travel in terrain beneath steep areas that slides might naturally run down. 

    Photo: Dallas Glass

Avalanche Discussion

Warm spring weather is upon us for the remainder of the forecast season, through the weekend. Sure, the weather feels like spring, but the snowpack hasn’t fully made the change. There is still relatively cold, dry, and layered snow beneath the now crusty or wet surface layers on more shaded aspects above about 4000ft. Predicting if and when any larger natural spring-shed avalanches will occur is nearly impossible. They often don’t completely correspond to the time of day. 

I took a late season snowmobile ride at the Kachess Sno Park Friday morning with NWAC non-profit board member Jon Ferrian. Surfaces were crispy, and we saw minimal previous avalanche activity on small steep slopes- just old rollerballs. Still, steep surfaces facing the sun were softening quickly and it didn't take long for riding to get better. Staying out into the afternoon would have been a very different experience, with many soft surfaces compared to our morning ride. We suspect snow will soften much quicker- and possibly avalanche on Saturday. 

At lower elevations, the snowpack has been through a lot over the past month. It’s largely changed over to spring and is thinning quickly. Our main concerns are lingering glide avalanches and rogue shedding block of snow, which could get you into trouble in the lower elevation band. As you ascend, the snowpack becomes much more aspect-dependent. All aspects aside from north have seen the full brunt of the sun this week. Any recent snow likely contains multiple crusts, or they may be integrated into the Early April Layer. On more shaded slopes at upper elevations you might still find a pocket of dry, settled snow. If you head to the tops of the higher peaks, you’ll probably find wind-affected snow. However, wind slabs have generally become unreactive. Even still, don’t ignore an obvious pillow-like slab sitting in high-consequence terrain. 

Other spring-time hazards continue to make travel a bit sportier than normal. Open creeks, holes, thin coverage, and exposed obstacle are common, especially below 4000ft and on southerly aspects.

Your avalanche, snowpack, or weather observations are extremely valuable to the avalanche community. Help create a more accurate forecast by submitting your observations HERE. 

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