Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The snowpack is strengthening and triggering a large avalanche is becoming less likely. Continue to use extra caution on very steep, rocky slopes, wind-affected slopes. Wet snow avalanches will be less likely today, but you may still find wet, soggy snow—primarily at middle and lower elevations.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    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. 

    ADDITIONAL DISCUSSION:The past 5 days of warming temperatures and intense sunshine have produced numerous wet loose avalanches. By and large, these have been on the smaller side and have occurred in predictable places—very steep, rocky slopes that face the sun. Today will be cooler and cloudier, and natural avalanches will be less likely. However, the snowpack received a poor refreeze overnight, and you may find that the snowpack at middle and especially lower elevations remains wet and soggy.  Avoid traveling on steep terrain where you find wet, bottomless mush.

    (3/5/2021) Persistent weak layers in the Banner Summit zone are showing signs of stabilizing - but they're still there. Here, a layer of surface hoar 3' down didn't fail during a snowpack test, but sheared when the block was pried out of the column. N, 8400'.

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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