Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The new snow is deep, fluffy, and tempting. Unfortunately, recent avalanches and audible whumpfs all point towards potentially dangerous unstable snow. Keep it dialed back by sticking to lower angled or treed terrain.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    There’s a lot of new snow at the Pass, especially up high in the terrain. The storm ended cold, leaving the snowpack mostly right-side-up and fluffy. However, temperature changes near the start of the storm along with periods of heavy snowfall produced a few subtle inter-storm layers. 

    You’re most likely to trigger a storm slab avalanche in wind affected snow, on very steep slopes, or near a convex rollover. These slides should be generally small, soft, and easier to manage but could step down into larger avalanches. 

    Even if there is “no slab” you may trigger dry loose sluffs that run far and fast, even in the trees.

    This skier triggered storm slab occurred in wind affected snow on Saturday. Photo: Kyle Rowe

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2

    Don’t expect to “gain confidence” in the snowpack as you travel. This isn’t a problem to figure out or outsmart. Recent avalanches, audible whumpfs, numerous snowpack tests, and well documented weak layers all point toward the same thing… the potential for persistent slabs. Sure you can find a test that doesn’t fail or a slope that didn’t slide, but tracks don’t mean it’s safe. 

    The only way to manage this tricky problem is avoidance. Steer clear of steep open slopes on shaded aspects. Snowpack tests and whumpfs suggest you could even trigger these avalanches at lower elevations.

    (2/2/2025)

    This avalanche released after a audible whumpf. The slide failed on facets over a crust and released the entire width of the feature. NE, 3700ft

    Photo: Summit at Snoqualmie Professional Patrol

Avalanche Discussion

The likelihood of avalanches is dropping but it’s not changing the danger or how we travel. Storm totals range from about 2ft near Pass level to 3.5ft at upper elevations. With such a strong cooling trend, most of this snow is very low density.

A few additional inches and some sunshine should be on tap for Tuesday. With cold temperatures, impacts from the sun should be minor, but you could see a small natural loose slide. 

All this new snow capped two well documented, but variable weak layers. The January Drough Layer (JDL) could include facets, surface hoar, and even thin crusts. Just below sits the thicker 1/10 crust. Facets have been seen on both sides of this layer. On southerly slopes, a strong melt-freeze crust exists. So far, we haven’t seen the same issues on sunny slopes as the more northerly aspects. 

The only way to look at these persistent weak layers is to dig, and dig, and dig. It will take more than one hole or a few tests to show anything. “Consistently, inconsistent” was the phrase one long-time snow professional used. Stay focused on information that clearly demonstrates unstable snow. 

Avalanches: Right now at the Pass, 3 avalanches appear to have failed on these layers. One from Saturday and two from Sunday. Additional slides have been reported in other forecast zones. As we head into a drier period, we’ll have to see how this layer changes.

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