Lawinenlagebericht

East Slopes South

Northwest Avalanche Center
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Lawinengefahr

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

You'll find more wind than new snow on Sunday. Blowing snow, recent drifting, and hollow drum-like snow surfaces are all signs that can help you pinpoint nearby wind deposits. These wind-drifted slabs won't be big but could be consequential in the wrong terrain, like large chutes or alpine features. 

Lawinenprobleme

  • Wind Slabs

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

    Look for a batch of shallow, small wind slabs to form as a  frontal system brings light precipitation ( <.10 swe) and increasing SW winds to the east-south. Some slabs may be easy to trigger if form on weak snow above the recent crust. These slabs won't be big, but could be consequential in extreme alpine terrain. You won't find these everywhere, but you'll most likely encounter them on the leeward side of ridges, on the breakover of steep unsupported slopes, and beneath rock and cliff bands. 

    Blowing and drifting snow should show exactly which steep slopes are loading up. Consider steering around pockets that look freshly drifted or if you see shooting cracks under your feet or sled. 

    (2/9/2024)

    You could trigger small wind slabs similar to this in the alpine on Sunday. 

    Photo: Harry Keane

Avalanche Discussion

The East South will unfortunately be rainshadowed out of this system. Sunday will likely just be a windy day along ridgetops with some light snow showers thrown in. 

Observers near Ahtanum Meadows on Saturday reported 3-6 inches of recent snow sitting on a stout ice crust. They also noted widespread surface hoar above 4800 ft.  While this surface hoar isn't super concerning right now, we'll want to pay attention to this layer as new snow starts trickling in. It could be a future weak layer that avalanches fail on once we build more of a slab.

Across much of the zone, you'll generally find 3-5" of new snow over the recent crust at mid and upper elevations, with more the higher you go. Observers in neighboring zones have been finding surface hoar over the early February crust, including forecasters on Tuesday at Blewett Pass. Any new wind slabs that do form could become reactive if they form over these types of grains. Check out another observation from the Wenatchee Mountains where they found collapsing of the new snow on the crust. 

We have limited information from upper elevations across the zone. The forecast team is unsure how the upper elevation snowpack is bonding to the pre-existing surfaces. So, as you climb into the alpine, ease into the terrain and be ready to make your own snowpack assessments before committing to larger terrain features. 

The lower elevation snowpack has endured a beating after last week's warm-up. Below 5000 ft you'll encounter plenty of shallowly buried objects, open creeks, and rough surfaces. 

Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at NWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

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