Bollettino valanghe

Gunnison

Crested Butte Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Although the likelihood continues to decrease, triggering a large and dangerous persistent slab remains possible. These avalanches are tricky and unforgiving — obvious warning signs like cracking or collapsing are unlikely before release. You may need to hit a thin spot or specific trigger point to collapse the weak layer, but if you do, the consequences will be severe. The safest options are slopes consistently less than 30 degrees or mid- to low-elevation southerly aspects. On west, north, east, and high-elevation south aspects, reduce your risk by choosing mellower terrain and avoiding convex rolls, shallow or rocky areas, and slopes with variable slab thickness from wind effects. 

Problemi valanghivi

  • Persistent Slabs

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

    Slabs over buried weak layers 1.5 to 3 feet thick are typically stubborn to trigger.  Obvious signs of instability are rare, and avalanches are most likely triggered from where slabs are thinner.  The north half of the compass has the most fragile weak layers buried in the middle and bottom of the snowpack and is most likely to produce remote-triggered, widely propagating, or destructive avalanches from steep or adjacent flat terrain (see several videos illustrating this).  At the lowest elevations, slabs may take on a moist or wetter flavor today.  Some higher-elevation southerly terrain also harbors problematic structures. The most reliable strategy for managing this problem is to choose conservative slope angles or travel on mid- to low-elevation southerly aspects.  Avoid traveling in or near steep terrain with variable snow depths or trigger points.  

     

    A pair of large persistent slabs below Scarp Ridge, which likely ran during increased winds on Tuesday, 2/24.  

    Photo: Irwin Guides

Avalanche Discussion

The likelihood of triggering a persistent slab is decreasing due to snowpack settlement during the recent dry, warm weather. Crusts of varying thickness have added some amount of strength to the snow surface, reducing, but not eliminating, the potential for triggering in areas that got well crusted. (See video from West Brush Creek).   Unfortunately, potential size remains deadly: most slab avalanches in the past two weeks were D2-D2.5, with some reaching D3.  Any avalanches triggered this week will likely be large enough to bury, injure, or kill you.  

Avoidance remains the easiest and most reliable strategy: heading towards lower-angle terrain or to aspects/elevations where the problem is unlikely: southerly aspects near and below treeline. Traveling on slopes where the snowpack is consistently deep and uniform, or where surface crusts are thick and supportable, offers reduced risk but with greater uncertainty.  Unless you are a gold medalist figure skater looking to take your skills to steep terrain, the reward of "riding" (sliding for dear life?) down the ice crusts on shady aspects is likely not worth it at this point.  Hopefully, an inch or two of new snow today will improve riding conditions on our crusty snow surfaces.  

Regioni coperte