Bollettino valanghe

Togwotee Pass

Bridger-Teton Avalanche Center
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Pericolo valanghe

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

In sintesi

Avalanche conditions will rise to the upper end of MODERATE today. New snowfall will be accompanied by strong winds. Watch out for areas of wind-stiffened snow up to a foot or more thick in exposed terrain at upper elevations. These slabs will be large enough to knock you off your feet and drag you into consequential terrain. Cracking and collapsing indicate that you have found unstable snow.

 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–1.5

    Togwotee has received 5-10 inches of low density snow in the last 5 days. Westerly winds on Monday backed to the south yesterday and have formed slabs along ridges and cross loaded terrain features such as gullies and rocky outcrops on leeward aspects. These slabs are sitting on a variety of weak layers formed during the December drought and will be reactive to human triggers. 

    These slabs could be over a foot thick and will feel denser than the sheltered snow that you traveled through at lower elevations. Watch for these deeper pillows along leeward aspects. There is a good chance you will have direct feedback under your skis or machine in the form of cracking and collapsing - sure signs that you found this problem. On steep northerly slopes, these slabs could entrain more sluff than you might expect given the surface faceting that developed during the last drought period in December.

     

    (1/8/2024)

    Winds were picking up and transporting snow along ridge lines. 

    Photo: Noah McCorkel

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Weak snow that formed during the November drought remains buried 1-3 feet below the surface. There has not been an avalanche on this layer in the Togwotee Pass zone for several weeks. However, the poor structure remains intact and with an increasing snow load this week, this layer may become active again.

    Surface hoar found preserved below 5" of new snow. West facing slope at 10,600'

    Photo: Noah McCorkel

Avalanche Discussion

The incoming storm cycle has the potential to change conditions quickly over the next several days. High winds today could rapidly increase surface instabilities, particularly in upper elevations and around terrain features that are exposed to the wind. A significant increase in weight added to the snowpack over the next several days could make it hard to predict when the new load will tip the stability balance and when we will start seeing an increase in avalanches. The current snowpack contains several weak layers (November drought, December Drought, surface hoar, crusts) that are about to be stressed.

When the equation becomes challenging with multiple variables (loading, wind, several weak layers) combined with some poor visibility, my solution is extra margin for error. This is probably a time to step back and adopt a more conservative mindset as we let the snowpack adjust. Continue to use safe travel techniques, watch for the obvious red flags (cracking, collapsing, avalanches, rapid loading…) and choose terrain that reflects the increasing hazard.  Overhead hazard will increase throughout the storm and triggering avalanches could happen from below steeper slopes. That might mean riding sheltered, lower angle slopes while the powder stacks up. Storms can be a very educational time to seek out small, safe test slopes to investigate current surface instabilities. We’ve waited a long time for this storm. A little more patience as we see how the snowpack adjusts to the incoming load will be well warranted. 

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