Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 6 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The mountains may feel relatively safe and stable, but several weak layers continue to lurk beneath the surface. Unfortunately, it will be nearly impossible to tell if any particular slope can slide. Spend time discussing the risk and consequences of these tricky avalanches before committing to steep open slopes.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    We seem to be entering a tricky period where avalanche activity has waned, but the snowpack remains weak and capable of producing slides. You could walk around all day and not see any obvious signs of instability. People may travel safely across steep terrain and nothing happens. Or, the slope you thought was safe may suddenly fail. Snow profiles and snowpack tests can highlight the unstable snow, but can't prove it's safe. There’s a pile of evidence from the past 10 days pointing towards danger. 

    So, how do we handle this? Talk with your group about the risk and consequences before stepping out into avalanche terrain. Then consider using smaller and planar slopes that are often less likely to slide. Choose lower consequence terrain that may help you get ‘lucky’ if you’re wrong. With a pile of uncertainty, one way to manage this challenging problem is just to avoid avalanche start zones altogether. 

Avalanche Discussion

Tuesday feels like a bit of a transition day in the mountains as we move from the beautiful spring-like weather of this past weekend to a more active pattern. We’ll be starting this storm off warm, with rain well into the mid-elevations. Fortunately, we aren’t expecting too much precipitation. In those few isolated spots where cold, dry snow still exists (higher shaded terrain), you may see small loose wet avalanches as rain starts to fall. Elsewhere in the terrain, a crust should limit the impact on the snow. 

Clear skies Monday evening should help wet snow freeze and form a new crust. This may vary greatly across the zone and by aspect, elevation, and slope angle. At higher elevations, this new crust will become our next storm interface. 

Persistent weak layers continue to hold our attention in the West South zone. There are two primary layers of concern. We don’t know the lower elevation extent of these layers, but it’s likely between 4500 and 5000ft. 

  • Northerly Aspects: Buried surface hoard and/or facets at the 2/13 interface can still be found and continue to produce significant test results. 
  • All Aspects: Sugary facets above, and occasionally below, the 2/7 crust are the most widespread layer of concern. 

The last pertinent avalanche we’re aware of occurred on Saturday, 2/28, near Darland Mt in the nearby East South zone. The snowpack structure in this area is very similar to locations near White Pass and Crystal Mt. 

One other problem we can’t seem to shake is the thin snowpacks, particularly at lower elevations and sunny slopes. Watch out for random holes, open creeks, and downed logs. 

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