Boletín de aludes

Boletín de aludes

Payette Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Snowfall from the weekend accompanied by strong winds have formed wind slabs at middle and upper elevations. These wind slabs are likely to be 1-2 feet deep. Watch for signs of instability as you approach exposed terrain near ridgetops. Persistent weak layers are widespread throughout our advisory area. Although unlikely, triggering a persistent slab avalanche would be large and destructive. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Our advisory area saw 1-2 feet of snow since last Friday. These storms brought strong east, southeast, and south winds. Wind slabs formed on leeward terrain features. Yesterday, we found north winds blowing on ridgetops above 7500' (see photo) . These recent north winds were forming slabs on southern aspects. You can expect to find wind slabs on different aspects of the compass in the middle and upper elevations as winds are forecasted to be from the north for the next 48 hours. 

    You can notice signs of wind slabs by observing how the snow feels at middle and upper elevations. Look for drifts and pillows of snow. Notice if the snow becomes stiff or slab-like in certain areas. If you feel a strong over weak setup on your skis or sled, you've found the recipe for wind slab avalanches. Stick to terrain features that don't have stiff, wind-deposited snow.

     

    (12/12/2022)

    Low visibility Monday (12/12) above 7500'. North winds were drifting snow and forming wind slabs at upper elevations.

    Photo: Studley

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    2–3

    We continue to find poor snowpack structure throughout our entire advisory area. Persistent weak layers (facets and surface hoar) are widespread at many different elevations and aspects. Overlying these persistent weak layers is a stiff slab from the snow that's fallen since late November. Stability tests have showed triggering a persistent slab avalanche to be unlikely.  So why are we still talking about this? 

    1. Poor structure is a red flag. We have strong, slabby snow overlying persistent, weak snow. Poor snowpack structure does not instill confidence to push our luck.
    2. Although proving stubborn and difficult to trigger, a persistent slab avalanche would be large and destructive (see video). 

    You are able to avoid this problem by sticking to terrain 30 degrees and under, or by locating slopes that already avalanched naturally during late November. 

Avalanche Discussion

Today's avalanche forecast is sponsored by Franklin Building Supply of McCall. Thank you for supporting the Payette Avalanche Center.

This past weekend's storms dropped 1-2 feet of snow (2" SWE). Over the weekend, storm snow instabilities were reported. Yesterday, whumphfing and collapsing were observed while traveling through the middle elevations. Storm snow instabilities may still be found over the next couple of days while traveling in the mountains. Watch and listen for these red flags. If you observe whumphfing or collapsing, dig down and assess before committing to steeper terrain. 

You can expect to see new snow shedding off trees and rocks this week. Temperatures are forecasted to be in the mid-20s this week with mostly sunny skies. This solar radiation will likely cause new snow to shed off steep rocky areas. Be aware of the terrain above as you're out in the mountains this week.

 

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