Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avalanche danger is Moderate this morning, and could rise to Considerable as daytime warming increases the likelihood of wet avalanches. Time your travel to be off steep terrain before meltwater penetrates more than a few inches into the snowpack. Wet avalanche hazards will increase through the week as the warmup continues (see video). On northerly aspects, triggering a large hard slab several feet thick remains a possibility. The greatest risk remains in thinner, variable snowpacks shaped by past wind drifting.

Avalanche problems

  • Wet Slabs

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

    Mountain temperatures will climb to near 50°F following a weak overnight refreeze. As meltwater percolates into the snowpack, it may pool on buried faceted layers, weakening bonds beneath slabs several feet thick. Wet slabs are unlikely early in the day while the surface remains frozen and meltwater production is limited. The hazard increases as the snowpack warms and free water moves deeper. The most concerning terrain is where previously dry snowpacks are transitioning to wet conditions this week—especially in steeper, rockier slopes. Many south-facing slopes have already made this transition, while high-elevation northerly aspects are unlikely to produce enough meltwater today.  

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–2.5

    Old, hard slabs 2 to 3+ feet thick overlie buried weak layers and are isolated and difficult to trigger. Without obvious warning signs, avalanches are most likely triggered where the slab is thinner and easier to impact the weak layer below.  Cornice falls can also act as triggers. You can reduce your risk by avoiding steep terrain with a thin or variable snowpack, such as rocky areas, rollovers, or places where wind has created uneven slab thickness. The southern half of the compass and slopes with consistently deep and uniform snow depths offer safer options.

    The last persistent slab avalanche in the Northwest Mountains ran in late February on Mt. Axtell.  It released below a cornice on a steep face that has avalanched multiple times this winter. 

  • Loose Wet

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

    As the upper snowpack becomes wet, shallow wet loose avalanches will become more common. In areas with a shallow and fully saturated snowpack, these point releases can gouge through the whole snowpack and grow larger. You can avoid this problem by traveling while the surface is still frozen or just beginning to soften. If you’re sinking past your ankles in wet snow, or you start to see rollerballs, pinwheels, or natural sluffing, it’s time to be cautious—especially above terrain traps or on long, steep slopes where avalanches can build volume.

Avalanche Discussion

Persistent slab issues linger on northerly slopes, generally near and above treeline. Unstable tests and avalanche activity over the past week have been concentrated in areas with shallower snowpacks—either the Southeast Mountains (ex. Whetstone) or zones on the Aspen side that often mirror our shallow structure (ex. Greg Mace Peak and near Snowmass). These avalanches have occurred in wind-drifted terrain with variable slab thickness.

The heatwave is upon us.  Last night was the first night with a poor refreeze; most weather stations are at or above freezing this morning. Predicting the onset of large natural wet avalanches always involves some uncertainty. This week’s record-setting warmup is complicated by a snowpack that has already been through multiple melt cycles on sunnier aspects, dense and wind-hammered surfaces that can delay meltwater percolation, and now a dust layer that may accelerate warming. As meltwater moves deeper into the snowpack, there is potential for large wet slab releases or wet loose avalanches that gouge deeper and grow to large sizes.

I expect terrain with a shallower, weaker snowpack—most often in the Southeast Mountains, or in the fringe terrain of the Northwest Mountains—to reach dangerous conditions sooner, though it’s unclear whether that happens today or holds off for another day. Either way, your decision-making framework is simple: travel early and watch for signs of decreasing stability signaled by surface crusts melting away and meltwater production increasing. These windows of safer travel will narrow as the week progresses. Hopefully, you’re back at the trailhead in flip-flops before things get sketchy, or splashing around with your Waverunner on mellower terrain.  

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