Bollettino valanghe

Northwest Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
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 snowpack has quieted since last week's storm, but the potential to trigger a large and dangerous avalanche lingers on a few steep slopes.  You are most likely to get surprised in wind-affected terrain where recent slabs are thicker or snow depths are shallow and variable.  Southerly aspects offer safer riding - stay alert for isolated wet loose instabilities if surface crusts thaw this afternoon.   

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    Last week's snowfall has settled into soft slabs ranging from 1 to 3 feet thick. The problem is larger and more common at higher elevation, wind-drifted terrain on the north half of the compass. Although many of these slabs are bonding well now,  instabilities may persist where they formed over a sporadic distribution of facets, surface hoar, or collapsible crusts on colder aspects.  Evaluate slab size, weak layer characteristics, and terrain consequences before riding on slopes steeper than 35 degrees.  

    There is also isolated potential for larger and harder slab avalanches to break on weak layers in the middle or bottom of the snowpack from early and mid-winter dry spells.  These avalanches are most likely to be triggered on the northern half of the compass and where the snowpack is unusually thin and weak. Be cautious of very steep, rocky, or wind-affected terrain with variable snow depths.    

    This persistent slab avalanche caught and carried a snowmobiler last weekend on East Beckwith. The avalanche broke on the January drought layer 2 to 3 feet deep in the middle of the snowpack.  Note how the terrain has variable depths and shallow areas due to wind effects.  (3/8/2025) Photo: Care Flight

Avalanche Discussion

Following a string of human-triggered avalanches and an accident near Marble over the weekend, slab activity has paused over the past two days. The avalanche danger is on a downtrend, with warm, dry weather helping to consolidate the upper snowpack.  There are several persistent weak layers of concern that you should evaluate before traveling in steep terrain. Issues are most concerning on colder aspects where the snowpack has seen limited meltwater this winter. 

Early March Weak Layer (buried 3/3):  Our most recent weak layer, buried by last week's snowfall, which significantly favored the Northwest Mountains.  Because this layer formed during the relatively warm and short dry spell in late February, it is generally not as weak or as well-developed as our deeper weak layers, thus quicker to gain strength. Slab avalanche activity on this layer has been almost exclusively near and above treeline, where slabs are larger and denser from the wind event that accompanied last week's storm.  Instabilities are most likely to linger on well-drifted slopes, though we can't rule out the problem in sheltered terrain where the recent snow buried unusually weak snow on an old bed surface or surface hoar.  

January and December Drought Layers (buried 2/8 and around Christmas): Well-developed facets and depth hoar layers formed during our month-long dry spells in December and January.  Our big storm in mid-February, the "Cupid Crusher",  buried these layers with harder slabs that are two to three feet thick or more.  Although avalanche activity and signs of instability on these deeper layers have quieted in recent weeks, they were the culprit in the Beckwith avalanches, Crystal Peak remote triggers, potentially the Baldy D3, and a few other step-down avalanches during last week's storm.  We still find occasional hard, propagating results on these layers in targeted shallow slopes (ex Snodgrass, Axtell).  These layers are best preserved in areas with relatively shallow snowpacks and most likely impacted by human triggers in thin parts of the slope, such as near rock bands or where wind-drifted slabs thin at their margins.

Our current snow surface could become another weak layer of concern, with snowy weather expected to arrive Thursday night through Saturday.  

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