Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 6 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanche conditions remain tricky, with signs of instability like cracking and collapsing becoming infrequent, but the consequences of a triggered avalanche remain severe.  A steady string of natural and human-triggered avalanches this week illustrates the dangers.  The worst snowpacks can be found on the north half of the compass and some high-elevation southerly terrain.  The unpredictable nature and dangerous size of avalanches can be managed through conservative terrain selection.  Stick to mellower slope angles without steep terrain directly above.  Southerly terrain offers a lower risk of slab avalanche, but warming conditions may create a loose avalanche hazard.  Loose avalanches become possible once you sink past your ankles into wet snow.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Slabs over buried weak layers 1.5 to 3.5 feet thick vary from stubborn to reactive under the weight of humans. These slabs are stiff and often do not show obvious warning signs before avalanches are triggered. 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, and destructive avalanches from steep or adjacent flat terrain (see several videos illustrating this).  Some higher-elevation southerly terrain also harbors problematic structures.  Manage today's persistent slab problem by choosing lower-angle and more conservative terrain without steeper overhead hazards on the aspects highlighted above.

     

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

    Photo: Irwin Guides

Avalanche Discussion

The main loading event that created the current Persistent Slab problem ended a week ago, yet a steady trickle of natural and human-triggered avalanches continued this week.  A few of these natural avalanches resulted from the rain-on-snow event on Wednesday, and a handful more came from wind loading at upper elevations.  The rain line on Wednesday extended to near summit elevations across the range and formed a crust on nearly all slopes.  Unfortunately, on many northerly slopes, this crust is relatively thin, and won't prevent you from triggering an avalanche, but it certainly ruins the riding conditions.  This remotely triggered avalanche from West Brush Creek on Thursday highlights the potential to trigger a dangerous avalanche on below treeline northerly slopes even when a surface crust is present.

Observers report fewer and fewer signs of instability this week, but the snowpack structure remains poor.  Cohesive slabs are well connected across the terrain, and weak layers have shown only modest improvement.  Riding steep terrain on the northern half of the compass is a gamble with serious consequences.  It may take more than one set of tracks to find a trigger point before an entire slope comes crashing down.  Conservative terrain selection is the simplest and most effective strategy for managing the problem.

Southerly terrain has a lower risk of slab avalanches except for some high-elevation southerly slopes.  Low and mid-elevation sunny terrain offers less slab avalanche risk and may provide the best riding conditions as the sun and warmth soften the snow surface.  Carefully monitor the surface for wetting and head to a cooler aspect with less sun if you sink past your ankles into mushy snow.  There is a small chance for loose avalanches to release a slab on very low elevation west and east slopes or on southerly slopes above treeline.  This recent avalanche near Cassie Peak illustrates this low likelihood event.

Regions covered