Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

You should encounter the windiest conditions of the week on Thursday. A fresh crop of Wind Slabs could develop in areas where you're not used to seeing them due to the atypical wind direction. Observing actively blowing snow is an easy way you can identify wind-loaded features where you have a higher probability of triggering an avalanche.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Wind speeds should increase throughout the day and may reach the strong category in the afternoon. With plenty of low-density snow currently available for transport, don’t be surprised to find some new slabs near ridgelines or the base of cliffs. Due to the atypical wind direction, these slabs may be on some unusual aspects. Look for actively blowing snow to help identify wind-loaded features you want to avoid. Textured surfaces, fresh cornices, and sharp drifts can also help you zero in on the location of possible Wind Slabs. 

    (3/4/2023)

    Wind slab near Gold Creek/Rampart Ridge on Saturday 3/4 that was formed during an east wind event.

    Photo: Griffin M

Avalanche Discussion

Most of the past week has been very similar, with patchy blue skies in the morning giving way to increasing clouds and snow showers in the afternoon. Each day winds have been just strong enough to drift a bit of snow around. On Thursday, the pattern begins to change and we are anticipating the biggest wind event of the week. 

On slopes that see direct sunshine, the amount of snow available for transport may be limited due to sun crusts formed during bouts of sunny weather this week. On more shaded aspects, the upper snowpack is still very soft and dry, meaning there is plenty of snow available for the wind to affect. 

Observations indicate that the upper snowpack is generally right-side-up heading into this storm cycle. That said, weak surfaces have been reported in recent days, and more concerningly, larger (D2-2.5) avalanches were reported earlier this week. On Monday, an avalanche professional spotted a deeper (~3ft/1m) natural slide in the Chair Peak Lake Basin (E, 5600ft). It may have failed on the 2/25 interface. Additional deep avalanches were spotted by avalanche professionals in wind-loaded terrain on Mt. Snoqualmie, with crowns estimated to be as much as 3 feet deep in places. Last Friday, we received word of a similarly deep avalanche occurring when an intentionally triggered small Wind Slab stepped down to a deeper (2.5ft/80cm) layer (N, 4300ft), also suspected to be the 2/25. Snowpack tests on this layer by NWAC forecasters have not been overly impressive, but we shouldn’t ignore these red flag signs heading into a larger loading event. If you’re going to see a deeper avalanche in the coming days, it will likely be on this interface.

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