Lawinenlagebericht

Togwotee Pass

Bridger-Teton Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
Keine Stufe
Open full map
Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Incremental loading of new snow this last week has formed firm, cohesive slabs in the upper elevations as well as stressed buried weak layers making human triggered avalanches possible. Dig down in the snow and test this buried weak snow before riding consequential slopes. Wind slabs will be confined to exposed terrain in the upper elevations.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    Weak layers are buried throughout the entire snowpack consisting of weak facets and crusts. The primary concern is the Feb 18th layer buried 1-3 feet above a firm, cohesive slab. This layer can be found across all aspects and elevations. Deeper weak layers also remain a concern due to the poor structure of well developed facets and depth hoar. Terrain with an increased likelihood of triggering one of these avalanches includes:

    • Shallow snowpack: Weaker buried layers of snow .
    • Wind-affected: Terrain where wind has formed firm, cohesive slabs of snow. 

    Steep: Over 35° slopes.

  • Wind Slabs

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

    Consistent snowfall during this last week combined with moderate S/SW winds has formed wind slabs that range 6 to 16 inches deep. These slabs will be most concerning in the upper elevations, but could be found in isolated features below 9000’. Areas with the highest likelihood of encountering a wind slab are exposed terrain such as ridgelines, cirques, or confined features like couloirs. 

    Watch for increased instability of new snow during periods of rapid warming on solar aspects if the forecasted cloud cover dissipates by this afternoon. Solar input on snow surfaces increases significantly this time of year with the arrival of spring.

Avalanche Discussion

Complacency

This last week brought a plethora of new snow creating excellent powder riding conditions. New snow instability has decreased, leaving wind slabs as the main avalanche concern. Yesterday afternoon, cloud cover broke in certain areas creating rapid warming of snow surfaces. This was the first significant warming of new snow that fell during cold conditions. This first wave of rapid warming causes increased instability of snow on solar aspects. Cloud cover could dissipate by this afternoon, so monitor the effect of direct sunlight on those southerly and westerly aspects. 

With the quick approaching arrival of spring and as new snow settles, it’s easy to become complacent assuming the snowpack has stabilized. Unfortunately we still have a complex snowpack. The Feb 18th weak layer is the primary concern as a firm, cohesive slab forms above. Areas such as Leidy contain a snowpack primed for avalanches on this weak layer. This layer can be easily identified by quickly trenching your sled through the firm slab to look at the structure and perform a quick stability test. These areas where you can easily trench down to that weak snow should warrant careful terrain management. Skiers and boarders will have a more difficult time feeling this layer while traveling in terrain. Step off your skis or board and dig a quick snowpit. It has been a long season, don’t let complacency throw off your mind set. Consequential terrain should always be thoroughly assessed as snow constantly evolves to changing weather conditions.

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