Lawinenlagebericht

Togwotee Pass

Bridger-Teton Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
Keine Stufe
Open full map
Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow combined with moderate wind has created unstable snow and added stress to weak layers buried 2-3 feet deep where consequential avalanches are possible on steep terrain over 35°. Use heightened caution on wind loaded terrain where multiple avalanche problems overlap. Assess the new snow stability across different aspects and elevations while identifying more dangerous wind loaded terrain.

Lawinenprobleme

  • Wind Slabs

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

    5-7 inches of the snow over the last 24 hours combined with shifting south to west wind has formed slabs up to 12 inches deep on wind loaded terrain. Triggering avalanches will be more likely the higher you travel in elevation and into more open/exposed terrain to the wind. Pay attention to wind slabs formed directly off leeward ridgelines and cross loaded terrain such as large gullies and cliff features. Look for signs of instability including stiffened snow surfaces, shooting cracks, or large pillow/drifts formed by wind. 

    New snow yesterday fell on a variety of snow surfaces and was reactive across most aspects on steep terrain over 35°. New snow could remain unstable in sheltered terrain today where loose avalanches are a concern. Assess new snow stability by performing quick hand shear tests and identifying how the new to old snow interface is bonding.

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–3

    Weak layers are most likely to be triggered where the slab is 2-3 feet thick and on very steep slopes over 35 degrees. Triggering a wind slab increases the possibility of an avalanche stepping down to buried weak layers. Signs of instability such as cracking, collapsing, or recent avalanches may not be present before triggering a dangerous avalanche. Multiple tracks on a slope do not indicate stability with this problem type. Suspect terrain includes very steep, rocky, and/or wind affected slopes where thin spots exist making it possible for humans to impact buried weak layers. 

    Persistent slab avalanches are capable of propagating widely across or up a slope. For this reason, it is not out of the question to trigger a larger hard slab avalanche with depths over 5 feet as a result of hitting a thin, shallow portion of the slope. Heavily wind affected slopes are where these avalanches could break deeper, such as this very large persistent slab on Lava Mountain that occurred on February 10th.

    The last human triggered persistent slab avalanche occurred on March 2nd in terrain similar to this.

    Photo: Dakota Richardson

Avalanche Discussion

New Snow Stability

Snowfall yesterday exceeded forecasted totals. This highlights the importance of taking forecasts with a grain of salt. Use forecasts as a starting point to help inform your riding plan, then make the real decisions once you’re out in the backcountry interpreting how the weather is impacting the snow and avalanches.  New snow yesterday was bonding poorly to the large array of snow surfaces formed prior to the storm creating widespread loose avalanches. New to old snow interfaces vary from widespread crusts on south-west-east aspects and areas of faceted snow on sheltered north aspects. Cooling temperatures should help new snow stabilize, but you’ll have to verify that yourself out there. Be on the lookout for wind loaded slopes, especially if you travel into alpine terrain around Two Oceans, Lava, Angle, or Breccia. Remember that the deep persistent slab problem is still lurking below the surface. Don’t test your luck on any potentially wind loaded terrain.  Seek lower angle, less consequential terrain and enjoy the improved snow conditions. 

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