Lawinenlagebericht

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

A steady stream of new and windblown snow is creating sensitive wind drifts and loading buried weak layers. Triggering an avalanche 1-3 feet deep is possible, especially on steep, upper elevation slopes. You can dramatically reduce your risk of getting caught in an avalanche by sticking to wind-sheltered, mid-elevation terrain.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    Early-season facets buried beneath a dense 3' thick slab are the top concern in this zone, but we can't rule out more recently formed weak layers (facets, isolated surface hoar, and crusts) in the top 2' of the snowpack. Slow but nearly constant loading from light snowfall and wind over the past 10 days are not giving these weak layers any relief.

    Despite an overall lower likelihood of triggering a slide, persistent slab avalanches are unpredictable on the best of days. If you find one of the land mines out there—and believe me, they exist—the MODERATE danger rating will mean little to you. Given the uncertainty surrounding these weak layers, skiing or riding in "prime-time", consequential avalanche terrain is a risky business.

    You are more likely to trigger an avalanche on upper elevation, wind-affected slopes steeper than about 35 degrees. Triggering a wind slab (see Problem #2 below) could step down into these persistent weak layers, resulting in a much larger avalanche. Long story short, you can greatly reduce your risk of triggering a large persistent slab avalanche (or a wind slab avalanche for that matter) by sticking to wind-sheltered, mid-elevation slopes.

    (2/13/2021) This intentionally-triggered avalanche above Titus Lake initiated in a wind slab and then stepped down to the weak snow near the ground. While this event is a week out, similar avalanches remain possible.

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Over the past 10 days, this zone has received a slow but steady trickle of snowfall accompanied by light to moderate winds. The low-density nature of the new snow has made it easily transported by even light breezes. Almost all open or sparsely treed, upper elevation slopes have experienced at least some amount of wind loading in recent days.

    Yesterday, observers reported that the gusty NW wind was transporting snow—primarily along upper elevation ridge crests, but even in some open mid-elevation terrain. Wind slabs may be found near ridgelines or mid-slope in exposed terrain. The redistribution of snow by the wind continues to tickle the beasts buried in our snowpack, and you're more likely to trigger a persistent slab avalanche (Problem #1 above) on wind-affected slopes. 

Avalanche Discussion

We are saddened to report that an avalanche fatality occurred Friday in Smiley Creek in the Western Smokys Mtns (7 miles S of Smiley Creek Lodge, 8 miles SW of Galena Summit). A group of visiting snowmobilers was riding near the head of the drainage. A portion of the group was playing on lower-angled terrain above the Smiley Creek Road when one rider broke off from the group and ascended an adjacent slope. While climbing the slope, he triggered a very large avalanche that broke 3-4' deep and over 500' wide. The rider was caught and carried by the avalanche. He deployed his airbag and was found on the surface by his partners, but had succumbed to the injuries he incurred during the slide.

The avalanche occurred on a south-facing slope at 9,100' and ran 1,000' vertically. The debris ran into a well-defined gully where it piled up to an estimated depth of 20-30'. The slope angle of the start zone was an estimated 35-40 degrees. The top portion of the avalanche path was wind-loaded, and this area has received nearly constant light snowfall over the past week. The avalanche fractured on a thin layer of faceted snow atop a slick crust that was buried by the late-January storm. In a crown profile lower in the avalanche path, we found this layer to be buried over 3' deep—the top 2' of the snowpack consisted of newer snow from the past week.

We performed a site investigation Friday afternoon—watch the video. More details—including avalanche specifics, a map, and additional photos—can be found here. We extend our sincere condolences to the friends and family of the victim and greatly appreciate their willingness to talk to us about the event. A full accident report will be published in the coming days.

Another avalanche fatality occurred in southeast Idaho yesterday. Some preliminary details can be found in this news report. Information about all U.S. avalanche accidents can be found on Avalanche.org.

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