Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
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Danger d’avalanche

Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering an avalanche in wind drifted snow remains possible in shaded, upper elevation terrain that was favored by snowfall two nights ago. In addition, watch out for wet snow at the mid and low elevations this afternoon as temperatures warm. Move to shaded aspects if you are sinking into wet and slushy snow.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Wind slabs with depths up to a foot deep may still be lingering in steep, shaded, and wind loaded terrain above 10,000’. These slabs are likely isolated to the northern half of the forecast area which received 5-7” of snow two nights ago. Watch for evidence of wind loading in steep terrain such as drifts or cracking.

    (3/14/2024)

    Cracking snow surfaces, a sign of instability on wind loaded terrain.  

    Photo: Alex Drinkard

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–2

    Melt-water created by a week of warm, sunny weather has made its way into the snowpack resulting in wet slab avalanches. Two notable wet slabs were triggered on the afternoon of March 19th, one by a human and the other by a snowcat (Wolf Trap, Bernie's Bowl). Even though we are trending towards cooler weather, water that has made it several inches below the surface hasn’t fully refrozen at the mid elevations. Therefore, wet slabs 1-2 feet deep remain an unlikely possibility this afternoon on rocky, south facing slopes below 9,000’. In addition, the snowpack on some low elevation slopes has become loose and unconsolidated due to poor overnight freezes. Monitor the snowpack for signs of warming. If you are sinking into wet, slushy snow then it is a good idea to seek colder aspects and steer clear of steep terrain.

    (3/19/2024) This avalanche was triggered by a snowcat pushing snow onto a ski slope Tuesday afternoon. 

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    Hard slabs 3-5 feet thick overlay weak snow that formed earlier in the season. Shallow, rocky, and unsupported terrain on the north half of the compass is where this problem has been most active. Right now, it is very unlikely that a human would trigger one of these slabs. Large triggers, like a cornice fall or surface snow avalanche, can still impact these deeply buried weak layers and initiate a much larger avalanche. Furthermore, an extreme loading event or a prolonged period above freezing has the potential to impact these layers. The current weather conditions do not warrant concern, but we will keep you updated in this problem section if they do. 

    The last reported avalanche involving deeply buried weak layers occurred naturally on March 5th after a significant loading event.

    (3/5/2024)

    Very large persistent slab avalanche that failed during the early March storm cycle. This terrain characterizes where this problem is most active. Very steep, unsupported slopes near cliffs. Also note the large cornices and potential trigger. 

    Photo: Dan Hays

Avalanche Discussion

Today will be a transitional day as we move towards a colder and stormier weather pattern. Temperatures are forecasted to climb well above freezing at the mid and low elevations. This combined with poor refreezes overnight have kept the wet avalanche problem on the radar for one more day. Sinking deeply into wet snow is a red flag and it is wise to avoid steep terrain if this occurs. 

Yesterday, there were reports of wind slabs above 10,000’ in the central Tetons. These slabs are not widespread and limited to steep, shaded terrain that was favored by recent snowfall. Light snow accumulation today shouldn’t be enough to create much additional concern. Still, watch for drifted snow if you are traveling in steep terrain in the highest reaches of the forecast zone.

Régions couvertes