Bulletin d’avalanche

Southeast Mountains

Crested Butte Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Storm totals through the week have reached around 1 foot. Slab avalanches remain possible to human trigger in the upper snowpack on wind-loaded slopes, and deeper in the snowpack in terrain highlighted by the persistent slab avalanche problem. Careful evaluation of both the snowpack and avalanche terrain characteristics will be necessary to manage these avalanche problems. The safest riding exists on wind sheltered below treeline slopes. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    The wind direction has blown from many different directions this week and created the potential to encounter a wind slab avalanche problem around the compass. These previously wind-loaded slopes remain the most suspect for triggering an avalanche today. Human triggering a slab avalanche in the upper snowpack on wind sheltered below treeline slopes is the least likely, but we can't yet completely rule out this potential. Consider avoiding steep slopes where you find more than a foot of thicker, denser-feeling snow.  Cracking in the snow is an obvious sign of instability. 

    An example of a wind slab from earlier this year.  

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Several large avalanches last week broke on faceted weak layers in the lower snowpack (Hunter Hill, Snowmass).  Recent persistent slab activity has been rare and most problematic on wind-drifted slopes at higher elevations.  Be cautious of similar terrain where wind drifting has formed dense slabs of varying thicknesses.  This loading event could make persistent slabs more reactive today.  

Avalanche Discussion

This week we have seen storm totals reach around 1 foot of new snow in the SE Mountains and up to 2 feet in the NW Mountains. Winds have been strong enough to transport snow at times and have blown from many different directions around the compass. Most notably out of the east yesterday which isn't a wind direction we often see. Wind speeds may be strong enough today, for periods of continued snow transport at upper elevations. This is one reason we are holding elevated avalanche danger for above-treeline elevations in the NW Mountains. 

Peak instability for the storm slab avalanche problem was reached early yesterday morning. During that time many small natural avalanches released and a few human-triggered avalanches also occurred. By the afternoon, this avalanche problem remained reactive on wind-loaded slopes, while in wind-sheltered areas the problem was quickly becoming more stubborn to human triggering. As we move further away from the loading period this avalanche problem will continue to become less reactive. As these slabs further settle and gain strength, we'll next need to observe whether any of the buried persistent weak layers in the upper snowpack will come into play. 

Looking ahead to Friday, we have a great weather forecast coming up and a lovely day to be out in the backcountry. High temperatures will be around the freezing mark and wet avalanche problems will be a developing avalanche problem throughout the day. Rapid settlement in the upper snowpack will keep some continued hazards going for recently formed storm slabs, while we'll further be assessing whether any persistent weak layers will come into play under those soft slabs. Start scheming some fun ideas for Friday, then make sure to check both the observations and the latest avalanche forecast to see how things are developing.

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