Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

The safest riding is where the snow surface is soft and protected from the recent wind event.  Last weekend's strong southwest winds formed stiff drifts on leeward terrain features.  Stay off of slopes with obvious signs of recent wind loading to reduce your risk of triggering an avalanche.  Wind slabs will appear smooth, rounded, and firm.  

Avalanche problems

  • Wind Slabs

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

    Strong to extreme southwest winds since Saturday afternoon formed drifts of varying thickness and hardness in wind-affected terrain.  Some slabs will be thick and dense enough to break above you.  Wind slabs are most common near and above treeline, but also exist on a few open slopes below treeline.  Cracking or collapsing drifts are obvious signs of instability, though feedback will become more erratic now.  Use visual clues to identify potential issues:  slabs will look smooth and rounded, typically below ridgelines, in gullies, or behind rollovers.   You can avoid the problem in wind-protected or wind-eroded slopes.   

    Several natural wind slabs ran in Redwell Basin on 3/5.  

Avalanche Discussion

Winds and transport are trending down compared to yesterday, but the damage has been done.  Ongoing snow transport yesterday produced a number of natural and triggered wind slabs, ranging from D1 to D2 in size, skewed towards the smaller end.  The wind event left dense slabs scattered across leeward terrain at higher elevations and in a few drifted areas below treeline.  The slabs are expected to be more difficult to trigger today, but they'll be just as troublesome if you do.  Sustained strong winds without new snow for fuel mean that many of the slabs are now hard and more challenging to manage or escape from.  The simplest strategy is avoidance until they have a few days to heal up.  You'll find softer, safer snow in wind-sheltered terrain or where the snow surface is rippled from wind erosion.  

With almost every wind event in the past month, we've observed one or a few persistent slabs release on windloaded slopes in the Southeast Mountains.  Over the weekend, a resident in Conundrum Creek (on the Aspen side) was engulfed in a powder cloud by a large persistent slab that ran naturally as wind transport intensified, and a similar avalanche crossed Express Creek Road.  Although the Aspen side has been the bullseye of persistent slab activity in the past couple of weeks, conditions are often similar in parts of our shallower zone where we don't get as much traffic or regular feedback. The persistent slab problem is most concerning near and above treeline in the Southeast Mountains, though isolated exceptions could exist elsewhere.  Most of our concerns involve facets or faceted crusts in the upper few feet of the snowpack. Well-placed stability tests can be helpful for identifying potential issues because the problem is certainly not everywhere.

Looking ahead, we're in a bit of a holding pattern with danger ratings as the sensitivity of wind slabs and persistent slabs gradually decrease, but remain possible in the near term.  

Regions covered