Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The daily orange flag is as persistent as the dangerous avalanche conditions we continue to face. This message has repeated itself like the string of human-triggered avalanches that have continued for the last 11 days! The most suspect areas to continue this string of avalanches would be on steep slopes facing west to north to east. Obvious warning signs have decreased, such as shooting cracks and a collapsing snowpack. Safer travel can be found on wind-protected southerly aspects, and as a bonus the consistent light snowfall has created good riding quality in many of those areas.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Soft slabs averaging 1 to 3 feet thick in sheltered terrain and larger in wind-loaded terrain will be most sensitive to triggers where they formed over fragile facets and collapsible crusts on west, north, east, and high southeast aspects.  Slab behavior is becoming more challenging as slabs stiffen and thicken, with dozens of recent remote triggers and slabs propagating wider across terrain features.  You may not see obvious warning signs, such as collapses or cracking, before triggering an avalanche.  Recent large human-triggered avalanches (Mt. Owen, East Beckwith, Mt. Axtell) highlight the issue.  You can reliably avoid the problem on slope angles less than 30 degrees without steeper slopes above you.    

    A snowmobiler remotely triggered this large persistent slab on Friday (1/2) while riding on the flat terrain below the slope.  

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Northwest winds on Sunday drifted the 8" to 16" of new, low-density snow into thicker drifts below ridges, behind rollovers, and in gullies.   The strongest winds and most favorable transport occurred above treeline, while some exposed near treeline slopes also developed more isolated drifts.   On larger terrain features or in heavily drifted slopes, slabs will be large enough to injure or bury you.  Moreover, a triggered wind slab could step down and release a much larger persistent slab described above.  Look for evidence of recent drifting in leeward terrain to identify the problem.  Wind slabs will look and feel thicker and denser than wind-protected snow.  Move to wind-eroded or wind-sheltered terrain to avoid this problem.  

    An example of a slab avalanche that broke below a leeward ridgeline earlier this season.

Avalanche Discussion

Are we setting new records? In our forecast area, human-triggered avalanches have occurred every day for the last 11 days! We've had some long strings of human-triggered avalanches before, but we must be approaching or have reached record territory by now. The most significant number of human-triggered avalanches occurred on December 28th and 29, but even if we narrow the range to the first 6 days of 2025, we still have 11 large human-triggered avalanches in the database. We may see a gap in this string of avalanche activity coming up as the backcountry becomes less busy during the work week, but unfortunately, the potential for this string of avalanche activity to continue is not decreasing very quickly. Where the snowpack is the most reactive is, of course, governed by aspect, as well as the total snow depth on those individual slopes. Zach made a few points on this in yesterday's discussion below. 

Southeast Mountains: Slabs are an ideal depth for human triggering, and the shallow and weak base below our holiday slabs is slow to improve.  Last weekend's observations consistently reported large collapses, easily triggered avalanches, and remotely triggered avalanches.  Ski patrol reports reactive and even touchy conditions as they work into new, untouched snowpacks (Ex. 1, Ex 2).  A large remotely triggered avalanche yesterday near Snodgrass paints the same picture of the obvious danger on terrain harboring persistent slab concerns, most commonly on west, north, and east aspects, and potentially windloaded southeast aspects.  

Northwest Mountains:  Slabs are thicker, and obvious signs of instability are diminishing, though we are getting occasional reports of collapses (ex., Schuylkill Ridge).  On low-angle slopes that hold the entire season's snowpack, the snowpack structure is gaining strength, and remote triggers are becoming less likely.  These improvements commonly signal a decreasing avalanche danger.  However, we have a unique and challenging setup this season because most of our steep terrain highlighted by the persistent slab rose lost about half of its snowpack to the widespread Thanksgiving cycle.  This means the snowpack is significantly shallower and weaker in start zones compared to low-angle slopes.  This makes it difficult for our forecasters to assess a representative snowpack safely and causes more uncertainty.  These forecaster observations from the Beckwith Range and Marble area (similar setup on the Aspen side) show our forecasters wrestling with this uncertainty and still avoiding avalanche terrain because of it.    Additionally, the wind slab problem is a threat at higher elevations.  Observers Sunday reported 16" of new snow in the Ruby Range, and with moderate northwesterly winds during that 24-hour period at high elevations, that low-density snow was easily redistributed into thicker slabs in leeward terrain.  

Regions covered