Bollettino valanghe

Tetons

Bridger-Teton Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Sustained wind around 20 mph out of the southwest combined with periods of rapid snowfall will create dangerous avalanche conditions in the upper elevations. Human triggered avalanches will most likely be on slopes where you encounter obvious signs of wind drifted snow such as cracking, stiffened surfaces, and large pillows. Avalanche danger will also increase throughout the day with snowfall rates of an inch or more per hour.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Wind increased yesterday to around 20 mph continuing today out of the west transitioning southwest forming fresh slabs 1-2 feet deep with the low density snow that is available for transport. In addition, continued snowfall today could reach rates of an inch or more per hour adding up to 10” of snow by this afternoon. The combination of increased wind and rapid loading will create fairly widespread new snow instability in the upper elevations. Look for open and exposed terrain in the middle and upper elevations where the snow has been drifted by wind forming stiffened surfaces, pillows and dunes. Avoid wind loaded terrain such as off ridgelines and remember that cracking snow surfaces is a clear sign of unstable snow. 

    (3/27/2024)

    A large natural avalanche that occured on Teewinot at 11,000' on an E aspect. Assess the recent snow stability with additional loading today and increased wind in the last 24 hours. 

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    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. Thin areas in the snowpack can act as trigger points and are most common in these locations. It is currently unlikely that a human would trigger one of these slabs. Larger triggers, like cornice fall or surface snow avalanches, still have the potential to impact weak layers buried deeply in the snowpack and initiate a much larger avalanche.

    The last reported avalanche on these persistent weak layers occured on 3/19 (Bernie's Bowl) in the form of a wet slab during a week of warm weather and strong solar influence. The last dry avalanche occured on 3/5 after a large and rapid loading event. 

    (3/5/2024)

    A very large persistent slab avalanche failed during the early March storm cycle. This terrain characterizes where this problem is most active: very steep, unsupported slopes near cliffs.

    Photo: Dan Hayes

Avalanche Discussion

Winter continues...

The snow has been stacking up throughout the week with 21" of snow and 2" of snow water equivalent reported at Surprise Meadows weather station, which has received the most snowfall. Less snow has been reported and found in the low and middle elevations. A Pacific trough and cold front brings a winter weather advisory to the Tetons today. Wind began to increase yesterday in the morning/afternoon (375 total miles of wind in the last 24 hours at JHMR Summit). Visible wind transport of snow was observed yesterday in the upper elevations. Snow that has fallen throughout the last week has remained low density and easy to transport by the wind. Combine this with rapid snowfall rates today and we will see increased avalanche danger. The snow that fell this week sits on a fairly widespread crust on W-S-E aspects up to 10,500’, with small facets developing around the crusts. Facet development on northerly aspects has been spatially variable, but most prominant in terrain sheltered from the wind. Recent snow has slowly been gaining strength on these poor interfaces. A natural avalanche was reported yesterday on Teewinot that failed on this poor interface above the forecast area. Higher elevations above the forecast elevation band have received significantly more snow. Keep this poor interface in mind as snow adds additional stress. Performing quick hand shear tests and assessing any recent snow instability will be critical while traveling in the mountains. Small sloughing and dry loose will be possible by the afternoon if forecasted snow totals pan out. Pay attention to changing conditions today as fresh wind slabs continue to form throughout the day. We’ve had fairly stable conditions throughout the last couple weeks, so don’t become complacent to increased danger today. Seek slopes sheltered from the wind and enjoy the fresh powder riding. 

Regioni coperte