Boletín de aludes

Southeast Mountains

Crested Butte Avalanche Center
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Peligro de aludes

Tue
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 5 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Strong northerly winds on Sunday may have formed thin, hard drifts on leeward terrain features.  Identify these smooth, small drifts and steer around them.  On the northern half of the compass, triggering an avalanche on weak layers deeper in the snowpack remains possible.  Slopes with highly variable depth due to rockiness, vegetation, or wind effect create more places to find a trigger point and increase the risk of an avalanche.  Consider choosing smaller terrain features with clean runouts to reduce the consequences of a surprise avalanche and avoid slopes with variable depth to reduce the likelihood of avalanche.

Problemas de aludes

  • Persistent Slabs

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

    Old, hard slabs 1.5 to 3+ feet thick overlie buried weak layers and are typically difficult to trigger. Without obvious warning signs, avalanches are most likely triggered where the slab is thinner and easier to impact the weak layer below.  Persistent slab avalanches are dangerous in size; they can propagate widely and be remotely triggered from adjacent low-angle terrain.  The most reliable way to manage this problem is to choose conservative slope angles or travel on southerly aspects, where the snowpack structure has become stronger and more spring-like. On northerly aspects, avoid steep terrain with a thin or variable snowpack, such as rocky areas, rollovers, or places where winds have created uneven slab thickness.

    This avalanche on Mt Whetstone is an example of terrain to avoid, with a thick slab transitioning to thin trigger points around its boundaries. Photo: Kelly Jensen

Avalanche Discussion

Persistent slab issues linger on northerly slopes, typically near and above treeline.  In the Northwest Mountains, the chances of triggering a slab that breaks on weak layers several feet deep have slowly become unlikely.  As you transition from the deeper snowpack to the west and northwest of Crested Butte into the shallower regions near town and to the east, the Persistent Slab problem becomes more probable.  Slabs become thinner, and weak layers are better developed.  Two recent natural avalanches provide supporting evidence to this idea.  Earlier this week, during a period of light wind loading, this avalanche failed on Mount Whetstone.  Another avalanche failed this weekend in the Aspen area, likely during Saturday night's wind event.  Both avalanches exemplify terrain with highly variable slab thickness due to wind effects.  Steer clear of this type of terrain in both forecast zones to reduce your chances of an avalanche.

An extreme wind event on Saturday night and Sunday blasted the landscape and transported snow.  In most cases, the snow disappeared into the atmosphere or ended up at the bottom of basins.  There could be a few isolated places where the wind formed shallow slabs in unusual places.  Identify places with smooth, hard textures and simply steer around them to avoid the potential trouble.

Cooler temperatures and gusty northerly winds keep most sunny surfaces frozen on Monday.  Wet avalanche concerns may be absent for another day or two before returning with vengeance later this week.  Temperatures soar 20-ish degrees above normal by the end of the week.  Expect loose avalanche activity to grow large and gouge into the snowpack.  Wet slab concerns develop later this week.

Regiones cubiertas