Lawinenlagebericht

Banner Summit

Sawtooth Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Be on the lookout for sensitive drifts and slabs of wind-blown snow. These slabs will be thicker as you climb in elevation. Cracking in the new snow is a clear sign of instability. While unlikely, we can't rule out triggering a much larger avalanche that breaks on weak layers deeper in the snowpack. These slides are most likely in very steep, rocky terrain with variable snowpack depths.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Wind slabs will grow in size today as wind and snowfall continue. Look for them near ridgelines and mid-slope gullies. As you climb in elevation, the slabs will be thicker and more widespread. Some slabs will overlie crusts and crust + facet combinations; avalanches could be easy to trigger in these areas and break wider than expected. Small chunks of cornice that you break off or that fall naturally could trigger wind slabs on the slopes beneath them. 

    Fortunately, managing this problem is straightforward. Avoiding wind-loaded slopes will significantly reduce the chances of finding trouble. Watch for fresh cornices, dunes, rippled snow, and areas with stiffer snow surfaces. These are clues that the wind has been at work. Cracks shooting in front of your skis or boards mean you've probably found a sensitive wind slab. Even small slabs can knock you off your feet or your machine. Consider the consequences of being caught before committing to riding steep terrain. 

Avalanche Discussion

A vigorous spring storm will continue through midday. Storm totals in this zone should reach 4-9", favoring the mountains near Banner Summit. Snowfall is accompanied by moderate S-SW-W wind. Both snow totals and the strength of the wind will increase as you climb in elevation. The level of avalanche hazard you find today is, for the most part, directly tied to these two factors.

Spring storms are hard to forecast and can have highly localized effects. If you can find snow without wind, you're in for a great and generally safe day of skiing and riding. Add sustained moderate to strong wind, though, and conditions can get spicy in a hurry. Today, I'd encourage you to prepare for the worst and hope for the best. Have a solid Plan B in place and anticipate increasing hazard as slabs grow throughout the day. 

While new snow avalanche problems should be at the front of your mind, we cannot overlook buried weak snow layers in the snowpack. Your odds of triggering a large Persistent Slab avalanche are low but not zero. These slides could fail on persistent weak layers, including crusts + facets on sunnier slopes and facets or surface hoar on shadier slopes. You can significantly reduce your risk by avoiding very steep, rocky, heavily wind-affected terrain on the N half of the compass. Here, the combination of stiff slabs and thin areas of the snowpack make avalanches easier to trigger. You probably won't experience obvious signs of instability like snowpack collapsing or cracking before triggering a slide. These avalanches can break well above you on the slope and be wider than expected. Avalanches triggered in shallow areas could involve much thicker slabs on the same slope.

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