Bollettino valanghe

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The snowpack is strengthening and triggering a large avalanche is becoming less likely. Continue to use extra caution on very steep, rocky slopes—especially where the snowpack is thinner (less than about 4 feet thick). Despite cloud cover and cooler temperatures, wet snow avalanches remain possible today—primarily at middle and lower elevations.

Problemi valanghivi

  • Persistent Slabs

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

    We've been plagued by persistent weak layers the entire season. First by early-season facets near the ground, then by weak layers that were buried in late-January and February. Warm temperatures and a lack of loading over the past 5 days have finally given these layers the breather they need. Observations from across the forecast area indicate that weak layers are stabilizing. Consequently—for the first time in well over two months—the likelihood of triggering a persistent slab avalanche has decreased to "unlikely." 

    There are two types of snowpacks in this world: those with persistent weak layers, and those without. Even if both snowpacks are considered "stable", I'd choose the one without weak layers every single time. So even as our snowpack trends towards stability, don't let your guard down. Even though triggering a persistent slab avalanche has become unlikely, that's not the same as impossible. If I had to describe where there's still a small chance of triggering a persistent slab avalanche, it would be on very steep (approaching 40 degrees), rocky, wind-affected slopes. Terrain like this is most common at upper elevations and especially in the alpine. 

    There's still a small chance of triggering a persistent slab avalanche, primarily in terrain like shown in the photo—very steep, rocky, and wind-affected. Johnstone Peak area.

  • Loose Wet

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

    The past 5 days of warming temperatures and intense sunshine have produced numerous wet loose avalanches. Most of these have been on the smaller side, but yesterday Scott observed a few in the Boulders that were large enough to bury a person. Almost all activity has occurred on very steep, rocky slopes that face the sun. The larger slides have generally occurred in areas where the snowpack is shallow and weak, allowing the wet sluffs to gouge down deeper into the snowpack and entrain more snow (see photo above/right).

    Although today will be cooler and cloudier, the snowpack received a poor refreeze overnight and there's likely a fair bit of liquid water lingering in the snowpack. Natural wet avalanches will be less common today, but on some slopes you're likely to find that the snowpack remains a wet, saturated mess and it's possible to trigger a wet slide. This will be most common at middle and lower elevations where temps will be warmer and the snowpack is thin and weak.

    (3/5/2021) This large wet loose avalanche naturally released in the N Fork of the Wood River drainage (S, 10100').

Avalanche Discussion

A winter of exceptionally unstable conditions has left many folks chomping at the bit to ski or ride in steeper terrain. As an avalanche forecaster, dropping the avalanche danger rating is always intimidating. It conjures up images of "opening the floodgates"—people flocking to avalanche terrain with reckless abandon. For obvious reasons, we hope this isn't the case. Here are some tips for managing the lingering avalanche hazard as the danger begins to decrease:

  • Remember that decreasing danger does not equal no danger. Read the forecast carefully to understand where there are still avalanche concerns. Even the definition of LOW danger states "Watch for unstable snow on isolated terrain features." Continue to factor these into your travel plans.
  • Speaking of plans, continue to make a travel plan with your partners that outlines what terrain is "off-limits". Once in the backcountry, stick to your plan and be prepared to step back if you see something you didn't expect.
  • Evaluate terrain carefully, and never stop paying attention to consequences. If you're considering riding or skiing a slope where triggering a slide would likely be fatal or result in a deep burial, you need to be very, very confident in the snowpack stability. If there's any question, choose lower consequence terrain.
  • Continue to use safe travel practices. Decreasing danger can result in folks entering avalanche terrain MORE often but using safe travel practices LESS often—a bad combination.

To summarize: keep doing what you've been doing all winter. The terrain you play in may change, but your practices, rituals, protocols, and systems should stay the same. Don't get sloppy—keep it tight!

Be sure to check out Ben's latest installment of our Weekend Update.

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