Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

With over a foot of new snow Monday night, avalanche activity will continue into Wednesday with our main concern being wet loose avalanches that could run naturally as the sun heats slopes. Mid and upper elevations may still have storm snow instabilities that could react to a human trigger. Avoid all steep slopes on Wednesday, and if you notice and natural avalanches avoid lower angle terrain beneath steep slopes in these areas as well. 

Problemi valanghivi

  • Loose Wet

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

    Your largest concern is wet avalanche activity with more sunshine on Wednesday. East-facing slopes will warm the most in the morning, then southerly midday and west in the afternoon. However, depending on cloud cover and the increasing sun height this time of year, avalanches may surprise you and impact much more of the compass than you might suspect. 

    Avalanches could run shallowly in the top few inches of snow, but they may run deeper, with the possibility of entraining large masses of snow that could take you for a dangerous ride. Most will probably be point releases that fan out, occurring naturally on any steep slopes, although they're more likely to initiate around rocks or trees, and near you if you venture into steeper terrain. At this point, we believe most activity will likely remain limited to snow above the Early April Crust, which in some areas is 2 or more feet deep.

    Avoid steep slopes with moist or wet snow, and if you notice any new avalanche activity then avoid low-angle terrain in the runouts of steep slopes as well. Shift your travels to terrain where you are not beneath large overhead hazards. 

    Example photo: Wet avalanche activity like you might see on Wednesday. Photo: Willie Webster

  • Storm Slabs

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

    We received over a foot of new snow Monday night and the snowpack needs more time to adjust and heal. Some storm slabs may be moist while others may be dry, and they could vary in size. Instabilities will likely have improved a little from the previous day, although we have a lot of uncertainty with conditions as we have very limited information. 

    Wind-loaded areas with drier snow at upper elevations are where you're mostly likely to trigger a slab avalanche. We don't suspect that slab avalanche activity will be limited to those locations. When snow moistens it may cause more slablike characteristics that could cause you to trigger an avalanche on a slope that you may not have been able to previously. In other areas, subtle variations in the storm snow layer causing an "upside down" snowpack may be enough for you to trigger a storm avalanche. 

    Give the snow more time to heal, and avoid slopes greater than 35° on Wednesday. This is especially the case on wind loaded slopes and in places with terrain traps below you. 

    Example of a human triggered slab avalanche similar to one that you might trigger on a steep rollover on Wednesday. 

    Photo: Jeff Hambelton - Elevated Backcountry

Avalanche Discussion

We're in the midst of fickle springlike weather with conditions changing constantly. Avalanche activity is unusual, where lines are blurred between wet and dry avalanches, and loose snow or slab avalanches. Despite the sunny skies, maintain elevated levels of caution and don't expect any avalanche activity to fit perfectly into the boxes that we've tried to fit them into. 

As temperatures increase a notch higher on Wednesday, chances of cornice failures or glide cracks releasing increases. This isn't the time to linger beneath either of these features. As days get warmer still, continue to give these features an even wider berth. 

Most snow will likely be wet or moist, and possibly sticky. Upper-elevation shady slopes may have dry snow. Snowlines are rapidly receding and hazardous holes are appearing in the snow at lower and mid elevations. Many low-elevation areas are below threshold, although large avalanches may run from higher elevations down into this elevation band. 

Your avalanche, snowpack, or weather observations are extremely valuable to the avalanche community. Help create a more accurate forecast by submitting your observations HERE. 

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