Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

Saturday is shaping up to be a pleasant day, but keep an eye out for lingering pockets of wind-blown snow in exposed terrain. These pockets won't be big but could knock you off your feet in the wrong spot. As the day heats up, look for rollerballs and or even some small, wet loose avalanches on sunny slopes. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Once the sun hits the dry snow, look for rollerballs and small wet loose avalanches on solar slopes. These won't be big but could be extensive along sunny aspects. The first places to shed snow are usually under rock bands in the sun or steep convexities pointing south. You can easily avoid this problem by steering around slopes once you notice the snow becoming sticky or gloppy. Rollerballs are great indicators that wet loose avalanches may soon follow. 

     

    (2/7/2024)

    An example of small wet loose avalanches in the Alpental Valley. You may see similar on Saturday. 

    Photo: Jonathan Spitzer

  • Wind Slabs

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

    Recent moderate/strong winds have drifted snow into shallow slabs at middle and upper elevations. Some slabs may be easy to trigger if they rest on weak snow above the recent crust. These slabs won't be big, but be consequential in extreme alpine terrain. You wont find these everywhere, but you'll most likely encounter them on the leeward side of ridges, on the breakover of chutes and couloirs, and beneath rock and cliff bands. As you travel, look for blowing snow or textured surfaces to help you identify where the problem lurks. Consider steering around pockets that look freshly drifted or if you see shooting cracks under your feet or sled. 

    (2/9/2024)

    You can trigger similar wind slabs on Saturday that will likely break on the recent crust. This small skier-triggered avalanche occurred in the Washington Pass area on Friday.  SE aspect, 7200 ft. 

     

    Photo: Harry Keane

Avalanche Discussion

Saturday is shaping up to be a pleasant day for mountain travel across the eastern mountains. Look for increasing cloud cover with rising freezing levels as a low-pressure system pushes milder air into the region. 

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 assessments. 

Across much of the zone, you'll find 3-5" of new snow over the recent crust at mid and upper elevations, with more the higher you go. Observers have been finding surface hoar over the early February crust, including forecasters on Tuesday at Blewett Pass. It was difficult to identify, but the feel of slipperyness over the crust beneath a few inches of new snow was a hint that it was there (see photo below). Any new wind slabs that do form could become reactive with potential for buried surface hoar or facets over the crust. Check out another observation from the Wenatchee Mountains where they found collapsing of the new snow on the crust. 

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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