Bollettino valanghe

Southeast Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Heightened avalanche conditions remain for northerly facing slopes where slab avalanches can release on a layer of faceted snow. This persistent slab avalanche problem has become more stubborn to trigger and is showing fewer obvious signs of instability, but by now means has it gone away. Colder temperatures and increased cloud cover have decreased the threat of wet avalanche activity. If you find your boots skinking deeply into wet snow, or an unsupportive wet snowpack, the travel advice is to head to lower angled slopes or a colder snowpack. 

Problemi valanghivi

  • Persistent Slabs

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

    You can trigger slabs 1 to 2 feet thick that fail on a layer of faceted snow. This avalanche problem has become more stubborn to trigger and is showing fewer obvious signs of instability after the last week of mild weather. Northerly facing aspects with slope angles near or above 35 degrees pose the greatest risk. Persistent slab avalanches can break above you, propagate surprisingly wide, or even be remotely triggered from an adjacent slope. The last human-triggered persistent slab avalanches occurred on February 28th, here and here. While 2 natural slab avalanches released around March 2nd, here. If uncertainty about the avalanche conditions arises, head to lower angled slopes and less complex terrain. 

    This photo from Cement Creek illustrates how persistent slabs can be triggered from a long ways away from the start zone.  The avalanche was remotely triggered by a snowmobile on 2/27.

  • Wet Slabs

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

    Clear sky and a nice freeze overnight, with cloud cover today, have all combined to decrease the thread of a wet avalanche. Snow surfaces are expected to mostly stay frozen today. However, if you find your boots sinking deeply into wet snow or an unsupportive wet snowpack, then the travel advice is to get out of steep terrain and head for lower slope angles or find a colder snowpack. 

    A natural Wet Slab avalanche from Monday 2/28.  Meltwater from warm temperatures and solar radiation infiltrated the facets from February and caused the failure of this dangerous slab.

Avalanche Discussion

Overnight the sky was clear while mountain temperatures dropped into the tweenies. This allowed snow surfaces to refreeze and turn off the source of the free water draining into the snowpack. Cloud cover today and high temperatures in the 30's are expected to mostly keep those snow surfaces frozen. This has allowed the loose snow avalanche problem to be dropped, and a decrease in the likelihood for the wet slab avalanche problem. We can't yet drop this wet slab avalanche problem because while the snow surface may be frozen, the free water that has accumulated in the snowpack has not yet had a chance to refreeze. There is still a low likelihood chance of seeing wet slab avalanche release today. 

The persistent slab avalanche problem is just kind of doing its thing. Its sensitivity to triggering continues to slowly decrease after the past weak of mild weather. East and West below treeline were dropped from the persistent slab distribution list, as a wet slab in these areas has become the main focus. We can expect further trimming for the distribution rose as we head into tomorrow and surface crusts have an even better refreeze. 

New snow avalanche problems and the persistent slab avalanche problem will drive the avalanche danger heading into the weekend. With the arrival of new snow, the avalanche danger will be on the increase. Right now, the avalanche danger is expected to reach CONSIDERABLE in the NW Mountains, and remain MODERATE in the SE Mountains. Forecasted snow doesn't currently look like it will increase the avalanche danger a full step in the southeast mountains. The avalanche danger will again be reassessed tomorrow morning and take into account new weather forecasts and how much snow has accumulated overnight. 

Regioni coperte