Avalanche forecast

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Sawtooth Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Triggering an avalanche large enough to bury you remains a worrisome possibility on slopes with old, weak snow at the base of the snowpack (upper-elevation slopes and shaded middle-elevation slopes facing W-N-E). Avalanches can be triggered after many tracks have already crossed a slope, and may break above you. You may get no warning signs of instability other than a destructive avalanche. Pockets of recently wind-drifted snow will be small but may be easy to trigger. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Triggering large, destructive avalanches involving 1.5-2.5 foot thick slabs on weak, early-season facets near the base of the snowpack remains a worrisome possibility. The ingredients for this avalanche recipe live on all upper-elevation slopes and middle-elevation slopes on colder aspects of the compass (W-N-E). On colder slopes, an easily identifiable, thick layer of weak, sugary facets sits underneath this slab. Weak snow will be harder to identify on more solar (SW-S-SE) aspects, in the form of a stack of facet + crust sandwiches that will require more attention to identify. 

    Without significant loading due to our drought, the snowpack is becoming less communicative. Obvious signs of instability like recent avalanches, cracking, and collapsing have all been decreasing — but not disappearing. Remain diligent in understanding that the snowpack structure remains for our persistent slab problem. Four out of the five people in your group could ride a slope and high-five at the bottom. But the possibility remains for the fifth to not make it back to the car that day. These slides have the potential to break above you from a distance away. 

    ADDITIONAL DISCUSSION:  A minor storm brought 3-5 inches of snow early Saturday morning. Moderate, gusty N winds pushed this snow around in exposed terrain, building small slabs that remain reactive to your weight today. In the steep terrain of the Sawtooths, slabs also commonly form on the aprons below cliffs and couloirs. These will be small, but can knock you off your feet in a consequential spot and run downslope quickly thanks to the stiff surfaces underneath.  Small loose snow avalanches involving this new snow will be easy to trigger on steep slopes. Small avalanches can be effective triggers for slabs failing on the weak snow near the ground. 

Avalanche Discussion

The Cambridge Dictionary defines persistent (adj) / per·​sis·​tent / pər-ˈsi-stənt as lasting for a long time or difficult to get rid of.  This, without a doubt, describes the weak facets we have in our snowpack that have lingered since late November and early December. These facets, or persistent grains, are what continue to keep our persistent slab problem alive and well. Most of you have gotten the picture by now that this problem is unfortunately not going anywhere, anytime soon. While it took a lot of force, I had a slab up to my chest fail in a snowpit and fall on top of me two days ago in the nearby Sawtooths — I tried to bottle up and carry this experience with me while I continued on my tour. While hard to imagine, these slabs will be large, destructive, and potentially deadly if triggered. This is not the time to beg for forgiveness instead of asking for permission from the snowpack.

We are living in the doldrums of an avalanche problem that doesn't give us much feedback to believe it's there. Very few natural avalanches, and decreasing signs of instability like cracking and collapsing make it difficult for us to stay steadfast in our paths of making safe choices in the mountains. I know I'm struggling while looking at soft northerly hallways that seem to "look safe" — whatever that means. A secondary definition of being persistentis continuing to do something in a determined way even when facing difficulties or opposition. I implore you to be like the slab, and remain persistent in your thoughtful decision-making in the mountains. 

You'll head out into a crisp, clear, and cold world today. Pay attention to the minor instabilities involving our newest snowfall: small, sensitive wind slabs and small, easy-to-trigger loose snow avalanches. These issues will be easy to identify and are unlikely to produce large avalanches on their own. But don't get distracted; remain persistent. The weak base of our snowpack should continue to be your primary concern. In this zone, a very dense, 1.5-2.5 foot thick slab is resting on top of these facets. This makes it more difficult to impact the weak snow underneath but also means that any triggered slides will be large and destructive. This weak snow will be more difficult to identify on solar slopes, where it exists as a mix of crusts and facets.  You're most likely to trigger these avalanches on steep, wind-affected slopes where the overlying slab has thin spots that make it easier to impact the weak layer. 

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