Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

On Friday, winds will shift back to the west and will be just strong enough to transport snow. You can trigger avalanches at middle and upper elevations in recently drifted snow. Watch for plumes of blowing snow and steer around steep slopes with freshly drifted slabs.

Problemi valanghivi

  • Wind Slabs

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

    Watch for blowing snow, stiff drifts, and cracks shooting through the snow as indicators of the danger. These are all signs to use caution and consider avoiding leeward slopes steeper than 35 degrees. Steer around convex features and drifted pillows. 

    On Friday, expect a shift to west wind with potential for blowing snow in the afternoon. Thursday was an active day of wind slab avalanches formed by strong south and easterly winds. Expect unique loading patterns on slopes that were exposed easterly valley winds. While large avalanches on older weak layers remain unlikely, they may not be impossible. Keep in mind that there are still widespread weak layers capable of producing surprisingly large avalanches. 

    (1/18/2025)

    An example from earlier this season of a small chunk of older wind slab, triggered by a skier. Jim Hill, NNE, 6,350ft

    Photo: Josh Hirshberg

Avalanche Discussion

Friday will be the beginning of a slow "warming trend" returning temperatures closer to normal. Expect a dusting of light snow overnight with a chance for partial clearing by afternoon. You can expect to find freshly drifted slabs from south and easterly winds. With a shift to west, winds may now be loading opposite aspects.

On Thursday, observers reported significant blowing snow and sensitive wind slab conditions. It appears that winds were more southerly and strong enough to forme fresh slabs on a variety of leeward slopes. As you travel through the mountains, assess localized wind loading patterns.

Under the newly forming wind slabs, the weak facets and surface hoar associated with the January Drought Layer (JDL) are still widespread on northerly aspects. With this loading, and more likely with coming storms, we could see persistent slab avalanche conditions become active. Stick to an "assessment mindset," step into new terrain slowly,  and assess the snowpack for strong over weak layering before committing to steep terrain. Choose lower angle slopes if you find a stiffer slab over weak, surgery snow or experience collapsing/cracking. 

Cold, mostly dry conditions in mid-February formed weak snow at the current snow surface. If/when we get more significant snowfall, this future new/old interface may be our first layer of concern. The Stevens Pass Zone picked up 2-3ft in the first week of February, burying the JDL. Following the initial storm, there were numerous reports of whumpfing collapses and some shooting cracks, but no reports of associated avalanches in this zone. In zones to the south and west, there were numerous reported persistent slab avalanches on the layer. Sunny days produced small wet and dry loose avalanches and formed a melt-freeze crust on southerly slopes. We're monitoring the JDL, as it's still weak and close enough to the surface to be a problematic weak layer with big enough future storms. 

You can help us build the forecast by submitting an observation HERE or via the Avy App. 

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