Bollettino valanghe

Southeast Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The most likely place to trigger an avalanche is on drifted slopes.  Gusty winds drifting snow at upper elevations could produce an isolated natural avalanche on leeward terrain.  There is a chance that avalanches break deeper in the snowpack on old, weak layers on slopes facing the north side of the compass.  Use caution or avoid slopes with recent or active wind loading.  Southerly-facing terrain without recent drifting offers a less problematic snowpack.

Problemi valanghivi

  • Wind Slabs

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

    Westerly winds have built thick slabs on the lee sides of terrain features over the last few days.  Slabs can release within the recent storm snow or step down into deeper weak layers where they overlap with the persistent slab avalanche problem.  Sunday evening and night winds shifted to the southwest and may find more snow to drift.  Fresh drifts are most likely found beneath cornices, below ridgetops, and cross-loaded into gullies.  Avoid terrain where you encounter signs of recent or active drifting.  Above treeline terrain will commonly have the most drifting, but you could encounter drifts at lower elevations closer to treeline.

    A human triggered slide from Coney's on Saturday. 

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    There is potential to trigger a dangerous slab avalanche on facets or depth hoar layers in the middle or bottom of the snowpack.  Persistent or deep persistent slab avalanches are most likely to be triggered on the northern half of the compass and where the snowpack is unusually thin and weak.  In rare cases, they might also be triggered on deeper slopes from step-down avalanches in the upper snowpack or cornice falls. Be cautious of very steep, rocky, or wind-affected terrain with variable snow depths and slopes receiving heavy windloading today.   Southerly slopes generally lack the problem due to previous meltwater strengthening the snowpack.  You can avoid the problem on slope angles consistently less than 30 degrees. 

    This notable natural avalanche ran Friday night or early Saturday morning. The avalanche debris pushed into the valley below. Schuylkill Ridge.

Avalanche Discussion

Snowfall totals from Thursday night through Sunday morning varied widely across the forecast zone.  In the Northwest Mountains, settled storm totals range from about 1 to 3 feet.  In the Southeast Mountains, totals are closer to a foot or less.  This difference in storm totals creates a notable difference in avalanche problems.

Northwest Mountains:  Over the past few days, most avalanche activity has occurred directly beneath the recent storm snow on a layer of faceted grains.  On Sunday, avalanches were triggered near Elkton and Schuylkill Ridge 1 to 2 feet deep.  This interface is the most likely place to trigger an avalanche.  You can encounter this issue on the north half of the compass in both drifted and sheltered terrain.  Assessing the snowpack to determine the likelihood of an avalanche can be challenging and lead to unpredictable results.  A simple solution is to select more conservative slope angles and smaller terrain features free from terrain traps.  A smaller chance exists for avalanches to break deeper in the snowpack like this natural avalanche from Friday night or Saturday morning on Schuylkill Ridge near Pittsburg.  Southerly-facing slopes have less problematic structures, but caution should be used around drifted features at upper elevations.

Southeast Mountains:  With notably less snowfall, new avalanche problems are largely patterned by recent drifting.  Although new avalanche problems are the most likely to be triggered, weak layers deeper in the snowpack are capable of avalanching.  Zach's observation from Cement Creek/Star Pass last week sheds more light on the potential to trigger an avalanche on old, weak layers in the middle or bottom of the snowpack.  Use caution if you travel near northerly-facing slopes with signs of recent drifting, as an avalanche that breaks in a recent drift could step down to deeper layers.

Cloud cover and gusty winds will likely keep snow surfaces cool on Monday.  The Wet Loose avalanche problem was removed from the problem list today, given the weather forecast.   However, air temperatures warm from previous days and could wet the snow surface on isolated sunny slopes, particularly if there's more sunshine than expected.

Regioni coperte