Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Large avalanches failing on weak snow near the ground remain a worrisome possibility. This problem is at its worst at upper elevations and on shaded middle elevation slopes (W-NW-N-NE-E). Slides can be triggered from a distance away from the slope that avalanches and may break wider than you'd expect.

Read today's Forecast Discussion for more info about what MODERATE danger with persistent slab instabilities looks like.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    The recipe for avalanches (slab+weak layer) exists in many places. Facets and facet+crust combinations are buried underneath dense, 1.5-2.5 foot thick slabs. This pairing is capable of producing large, destructive avalanches. You'll find this snowpack structure on all upper elevation slopes and shaded middle elevation slopes (W-NW-N-NE-N). 

    As you're traveling, look for obvious signs of instability such as cracking and collapsing. Pay attention to these warnings, but don't let a lack of them lull you into a false sense of security. These types of weak layers can produce avalanches long after loading events. You can dramatically reduce your risk of tangling with a large avalanche by avoiding slopes where this weak snow exists at the base of the snowpack.

Avalanche Discussion

SCARY MODERATE

The Avalanche Danger Scale is an imperfect tool. The danger has dropped from CONSIDERABLE to MODERATE today because the likelihood of triggering an avalanche is gradually decreasing as days pass without loading. This color change is not a sign that entering avalanche terrain is now safe. While playing in big avalanche terrain in big mountains is one of my favorite things to do, that's not where you will find me today. Why? Read on.

Avalanches are most likely during and shortly after loading events. When new snow bonds well to the snow underneath, the likelihood of triggering avalanches can decrease quickly. However, when new snow falls on persistent weak layers, this decrease in the likelihood of triggering slides happens at a much, much slower pace. Traveling in the mountains with a long-lasting persistent slab instability tests our patience and decision-making, particularly in these periods of gradually decreasing likelihood.

Yesterday, my partner and I walked above and gazed longingly down many steep slopes covered in soft snow. Had we been there a few days ago there is a good chance we would have been remotely triggering large avalanches from the ridge we walked on. But yesterday the snowpack was disconcertingly quiet. Despite this fact, we stuck with our choice to avoid that type of terrain. You're likely to observe fewer obvious signs of instability today than you did last week, but the weak snow at the base of the snowpack hasn't gone away. It's a little harder to "wake" this snow up, but if you do the outcome will be just as bad. I'm not trying to preach to you, I just want you to understand the type of environment that you are heading out into.

If you choose to ski or ride steep avalanche terrain in areas with weak snow at the base of the snowpack you are rolling the dice. There isn't a better way to put it. Today, you may ski your desired line and get to the bottom with a smile on your face. Or, you may trigger a large, destructive avalanche that breaks well above you and launches you downslope at high speed through rocks and trees. Picture being in a bad car crash without the car to protect you. I encourage you to continue to exercise your patience today. The season has just begun and we will find windows of better stability and better coverage down the road, but we're not there yet. 

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