Boletín de aludes

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The avalanche danger will rise to MODERATEas sustained sunshine melts snow surfaces throughout the day. Small loose snow avalanches will become easier to trigger throughout the day on steep slopes facing the sun where the snow surface feels moist. These can start small but gain speed and size as they move downhill. Be on the lookout for wind-drifted pockets of snow that will be sensitive to your weight. Triggering large avalanches that fail on deeper weak layers is most likely in very steep, rocky, alpine terrain.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–1.5

    Unimpeded, sustained sunshine has been soaked our mountains all day yesterday for the first time since recent storms, and will continue today. This morning starts out warmer than yesterday, with a weaker freeze in most locations last night. The 8-12 inches of fresh snow from the past week will moisten throughout the day. This newer snow sits on top of crusts from over a week ago. As surface snow melts and water percolates down to these crusts, it will become increasingly easy to trigger loose avalanches in this wet snow. These are most likely on steep slopes that face the sun, will start out small, and can gain speed and size as they run downhill.

    Luckily this problem is easy to identify and manage through timing. Starting early and planning for an earlier exit will allow you to be off of steep slopes before this problem is at its worst. If you're encountering wet snow on a steep slope and your skis are sinking farther into it than earlier, it's likely time to get off the slope. These will run naturally during the heat of the day. 

    (3/17/2024)

    Many wet loose avalanches and a wet slab avalanche  a S/SE slope near 10,100' close to Galena Peak. 

    Photo: Brooke Maushund

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    A wind event in the Boulder Mountains built fresh shallow new wind slabs yesterday morning.  These proved to be reactive with two human-triggered avalanches on separate aspects of Galena Peak yesterday — one of which caught, carried, and partially buried a snowboarder. While these slabs were only 3-5 inches thick, due to their fresh nature they were reactive in specific alpine terrain. These built on top of the slightly thicker, more stubborn wind slabs built by variable winds in the previous 5 days.

    Keep an eye out for recently formed drifts of wind blown snow. Drifts, pillows, and textured surfaces are all signs that the wind has been at work. If you experience the surface of the snow cracking or feel the density of the snow beneath your ski, board, or machine stiffen and sound like scratching styrofoam — it's a sign you're walking through one of these slabs. These will be most common at upper elevations near ridgelines, in mid-slope features like gullies, and on the aprons of open alpine bowls. If the snow surface is textured or the snow you are moving through becomes stiffer or cracks, it is a sign you are moving through wind-effected snow.

    As the day warms us, be aware of old large CORNICES lingering both overhead and on ridgelines you may be traveling on. The chances of one of these failing will increase throughout the day.

    (4/1/2024)

    This avalanche was triggered by a rider in the NW bowl of Galena Peak on 4/1/2024.

    Photo: Ben VandenBos

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    2–2.5

    Weak layers buried under dense slabs in the upper few feet of the snowpack have had some time to rest, but they haven't gone away. The consequences of triggering an avalanche involving this weak snow would be severe. If you dig down, you'll find facets and bands of surface hoar on shaded slopes and icy crusts with associated facets on slopes that face the sun. 

    You will not receive any warning signs before triggering one of these slides. The first sign of instability would be the large avalanche you trigger. If triggered, these slides may break well above you on the slope and fail widely. You can drastically reduce your risk of encountering a slide like this by steering clear of very steep, rocky, heavily wind-affected terrain. 

Avalanche Discussion

Walking out into the mountains there are three considerations you should have today in the Galena Summit & Eastern Mountains zone. 

WARM & WET: The mountains saw their first dose of sunshine since recent storms yesterday. Solar input and even warmer temperatures continue into the day today with a weaker freeze overnight and warmer temperatures this morning. This will melt the snow surface throughout the day, increasing the likelihood of wet loose avalanches as the day goes on. These will be most likely on steep slopes that receive direct sunshine, and below rocky outcroppings and cliffs. While these will likely be small, expect the wet snow to carry enough force to knock you off your feet in consequential terrain. Timing and situational awareness will be key to managing this problem. Pick a turn around time and stick to it. 

WINDED: Although not registered on our mid-elevation weather stations, a moderate to strong wind event took place in the Boulders two nights ago into the morning yesterday. This built new wind slabs in the alpine that proved to be reactive to human triggering— one of which caught, carried, and partially buried a snowboarder.  This is in addition to the round of settling slabs from several days prior that were largely stubborn to unreactive prior to this event. While these slabs will be relatively small, considering them in your travel plans will be essential to a safe day in the mountains. You are most likely to run into this problem near ridgelines, in mid-slope features like gullies, and on the aprons of large alpine bowls. Visual clues like wind scouring on windward slopes, texturing on leeward slopes, and dune-like featuers will be your best bet to identifying where this problem lives. As the day warms us, be aware of old large CORNICES lingering both overhead and on ridgelines you may be traveling on. The chances of one of these failing will increase throughout the day.

WEIRD: While the chance of triggering an avalanche on deeper persistent weak layers is unlikely, it is not impossible. Triggering one of these is most likely in very steep (>45 degree), rocky, alpine terrain — which is quite common in this zone. Know that while the chances of triggering one of these slides is low, that your chance of surviving one of these beasts is equally low.  

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