Boletín de aludes

Northwest Mountains

Crested Butte Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó last year. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

You can trigger a dangerous slab avalanche without warning on some slopes like these recent human-triggered slides from East Beckwith Mountain and near Schuylkill Peak.  Don't let a lack of cracking and collapsing or the 'spring-like' weather convince you that avalanche conditions are safe.  The most hazardous slopes are often on the northern half of the compass and at upper elevations but can extend below treeline.  If you are uncertain about the snowpack on suspect aspects, choose lower-angled terrain and low-consequence slopes to reduce your risk.  Southerly-facing terrain offers a less hazardous snowpack, but loose avalanche problems could develop on sunbaked slopes.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–2.5

    2 to 4 feet of new snow has accumulated since March 3rd. That snow has settled into a slab over a variable distribution of small facets, surface hoar, and collapsible crusts. This new persistent slab avalanche problem is the most reactive on previously wind-loaded terrain. The avalanche problem becomes more spotty in distribution on lower-elevation wind-sheltered slopes.  Consider evaluating the slab characteristics over these persistent weak layers in your area to identify problematic structures or manage the potential avalanche problem through your terrain choices. Such as choosing lower-angled slopes and/or avoiding slopes with terrain traps like rocks, trees, or gullies. 

    Some avalanches can break in the middle of the snowpack on a weak layer that formed during the prolonged drought in January and early February, like these triggered avalanches near East Beckwith Mountain.  An even smaller chance exists for avalanches breaking near the ground on weak layers from early winter.

    A snowmobile triggered slab avalanche in the Kebler Pass area. March 8th. Photo: Care Flight

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    As the sun warms the snow surface, wet, loose avalanche activity will become possible. Some lower elevation slopes with a northerly component could also produce wet avalanche activity as a mostly dry snowpack becomes wet at the surface.  Multiple days of warm conditions have gradually eased concerns about wet avalanches on some sunny slopes.  Cloud cover develops around midday and may help reduce the threat of wet avalanches due to slightly cooler temperatures and less solar radiation.

    These wet, loose avalanches grew larger when they pried slabs off the southeastern side of Cascade Mountain.

    (3/8/2025)

Avalanche Discussion

Two storms rolled through the area over the past week, depositing roughly 1 to 4 feet across the forecast zones, with areas in the Northwest Mountains receiving the most snowfall. Avalanche activity peaked during the storms, but human-triggered avalanches continue (list from the past week), including one accident just north of CBAC forecast boundaries near Marble.  The pattern of human involvement is easy to interpret; you can trigger a dangerous slab avalanche without warning signs.

This season has been characterized by a few significant stormy periods and several drought periods when nasty, persistent weak layers formed.  The stormy periods caused significant natural avalanche cycles, leaving a hard-to-predict patchwork of snowpack structures across the landscape, particularly on the north half of the compass at upper elevations.  The most recent avalanche activity occurred on the weak layers buried on March 3rd.  This interface is the most likely place for you to trigger a slab avalanche. Still, in some rarer cases, you could trigger an avalanche on weak layers formed during the January/February drought.  These avalanches from East Beckwith are examples of this possibility.  A triggered avalanche on the upper weak layers could 'step down' to weak layers deeper in the snowpack on upper elevation slopes.  

Warm weather continues on Tuesday, leaving open the possibility of wet avalanche activity.  On Monday, forecasters triggered a Wet Loose avalanche on a northeast slope below treeline.  Cloud cover increases around midday and may reduce the threat of wet avalanche activity.  Temperatures were a few degrees warmer last night than the previous and could rise further during the day, depending on when the cloud cover arrives.  Carefully monitor surface wetness, particularly on slopes with a mostly dry snowpack and a few inches of wet snow at the surface, like you might encounter on lower elevation shady slopes.     

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