Bollettino valanghe

Northwest Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Wed
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Following a good refreeze last night, the snowpack is generally stable.  Stay alert for isolated exceptions.  These could be small wet avalanches later today or a larger slab avalanche from a steep, rocky slope with variable snow coverage.  Continue to practice sound travel protocols, exposing only one person at a time to avalanche terrain.  

Problemi valanghivi

  • Persistent Slabs

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

    Hard slabs that break 2 to 6 feet deep on weak layers near the ground remain a low likelihood concern.  The problem has become increasingly stubborn and isolated, and it has been several weeks since we have observed a persistent slab avalanche.  There is lingering uncertainty that skiers or riders can trigger a large avalanche from the margins of the slab where it thins out,  especially at higher elevations.   Cornice falls can also trigger large avalanches.  You can reduce your risk by traveling where the snowpack is deeper and more uniform.  Regroup in safe zones that are clear of unusually wide and long-running avalanches.  

    An example of a thick, hard persistent slab that released naturally in mid-February.

Avalanche Discussion

With the meltwater water factory on pause for the past 36 hours and clear skies last night promoting a solid refreeze, wet slab concerns are diminishing.  Sunny skies and warm temperatures will thaw the snow surface today, and you can still encounter small wet sluffs in steep, rocky terrain.  If you are traveling on the west side of Kebler Pass outside of the strong Crested Butte inversion, you may encounter larger wet avalanche concerns developing below treeline this afternoon.   It's always good practice to stay off of steep slopes if the snowpack is saturated and unsupportive. 

The persistent slab problem remains on everyone's radar because of how unusual and active it was up until late February.  Our last reported persistent slab failed on February 24th, and we've received only a couple of reports of collapses since then.  Given the prolonged period of relatively dry weather since mid-February, buried weak layers have had a chance to adjust to the large slabs resting above them.  While improving test results and a lack of activity in the past two weeks all point to a very low chance of triggering one of these avalanches, we suspect there are a few land mines still lurking out there.  Additionally, large cornice falls can act as triggers.  Continue to practice caution with this problem by reducing your exposure through sound uproutes, riding one at a time, and regrouping in zones that are safe from the threat of large avalanches.  

Tonight we transition into a prolonged stormy period.  Expect the danger to rise as fresh storm instabilities develop.    The rising danger will initially impact the Northwest Mountains, where storm totals will be larger, and higher elevations, where winds will be drifting the new snow.  

Regioni coperte