Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Wednesday will bring the last shot of warm conditions before a cold storm moves in for the end of the week. Stay alert to what is above you and limit time spent under large cornices and glide cracks. Avoid travel on or directly below steep slopes as the snow becomes wet, soft, and unsupportable.

Problemi valanghivi

  • Loose Wet

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

    Below-freezing temperatures and clear skies overnight will build a crust out of wet snow surfaces. The crust will prohibit wet loose avalanches in the morning. After it melts you could see them return.

    You are more likely to see wet avalanches on slopes facing the sun. Lots of slopes have produced wet loose avalanches but that doesn't mean there can't be more with prolonged warming.

    They are more likely to naturally release when the snow is wet and unsupportable. You might even get one moving on a steep slope.  Wet loose avalanches commonly initiate in rocky or treed terrain. Keep an eye on what is above you and limit time spent on or below steep slopes of wet, sloppy snow.

    (3/21/2023)

    Fresh wet loose avalanches on the south side of Shuksan Arm. Wet avalanche activity picked up at 2pm in this area.

     

    Photo: Mike Elges - Cascade Mountain Ascents

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3

    Glide avalanches, wet slabs, and cornice fall all become hazards during extended periods of above freezing temperatures. Cooler temperatures and a clear sky Tuesday night won’t do much to affect the likelihood either way. In addition to being large and powerful, they can also trigger larger avalanches in much deeper layers.

    Avoid traveling directly under big cornices and glide cracks. There isn't much you can do about these types of avalanches other than stay out of the way. 

    (3/21/2023)

    A natural glide avalanche was observed on Tuesday 3/21 on the E side of Granite Mt/Snoqualmie Pass. Additional glide cracks can be seen on the adjacent slopes.  Approx: E, 4600ft, (WS-N-D2-R2-G).

    Photo: Alpental Patrol

Avalanche Discussion

Observed avalanche activity Tuesday consisted of a few varieties of wet avalanches. A team on Mt. Ann in West North reported fresh wet avalanches to D2 initiating in cliffy terrain on the south side of Shuksan Arm. They also found a supportable crust near and above treeline with enough of a dusting of new snow to make for decent turns. Southerly aspects softened through the day while shaded aspects stayed crusty into the afternoon.

A very large avalanche (D3+) was reported Sunday from below the West Face of Sloan Peak in West Central as well as a large glide avalanche (D2) at Snoqualmie Pass on Tuesday. Both were naturally triggered. While avalanches like these are not widespread across the west side of the Cascades, they're out there and are a direct result of prolonged warming.

A skier fell through a snow bridge spanning a glide crack on Table Mountain (West North) on Sunday. There was no sign of a glide crack below the snow surface and other skiers and riders had already traveled across in the same spot. The skier fell a good distance into the crack but was not injured. While not an avalanche problem it's another reminder that warm temperatures are changing and weakening the mountain landscape in ways we can’t always see. 

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