Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Strong winds from the west to the northwest on Tuesday Night and Wednesday, have left behind fresh wind slabs that will remain your primary avalanche hazard today. Several human-triggered wind slabs were also reported on Wednesday, here and here. The most likely areas to encounter this avalanche problem will be on the lee sides of ridgelines and cross-loaded terrain features. A clear sky overnight and low temperatures in the teens have combined to finally eliminate wet avalanche concerns. If a loose wet avalanche problem were to develop today, it is expected to be isolated and small in size. 

Avalanche problems

  • Wind Slabs

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

    Accumulating snow on Tuesday and into Wednesday, combined with strong winds from the west to northwest, created fresh wind slabs. On Wednesday there were several human-triggered wind slabs reported, here and here. In general, this avalanche problem remains small in size with crowns averaging 6 to 10 inches. However, on some alpine terrain features, these slabs could be over 12 inches thick. This avalanche problem may feel more stubborn to human triggers today and give little warning until just the right slope or trigger point is found. The most common locations to encounter this avalanche problem will be on the lee sides of ridgelines and cross-loaded terrain features. 

    A ski cut released this wind slab on Wednesday March 30th. ESE, 11,900ft.  

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2

     Slab avalanches breaking into old snow layers have become unlikely to trigger, but this avalanche problem can't be 100% eliminated. The last reported persistent slab avalanche in our area was reported on March 18th, here. The most likely areas to still trigger this avalanche problem would be on a northerly facing slope, potentially from a trigger point where the snowpack transitions from deep to shallow near rock outcrops or wind-eroded terrain. If you choose to ride steep terrain on the northern half of the compass, don't expect any obvious red flags related to this avalanche problem, and plan your regrouping areas outside of the potential avalanche runout. 

    This large persistent slab avalanche was remotely triggered on 3/18. 

Avalanche Discussion

After the recent heatwave, below freezing temperatures arrived on Tuesday night, but cloud cover limited the snowpack's ability to lose the heat it has soaked up. Think of the cloud cover essentially working like an insulated blanket over the snowpack. Now on Wednesday night, we had a clear sky with low temperatures dropping into the teens. Those conditions are expected to have created a good freeze overnight and eliminated wet avalanche concerns. If you happen to find an isolated area where you are sinking deeply into wet snow, that would not be a good setup for traveling in steep terrain. Any loose wet avalanche concerns that develop from today's clear sky and strong spring sun are expected to be small and isolated. The recent snow that accumulated on Tuesday into Wednesday has already settled down close to the old snow surface, or it has been buffed by the recent strong winds. 

All of yesterday's reported wind slabs were documented to have released within the storm snow on non-persistent snow grains. Those same slabs will now have grown more stubborn to human triggering. However, an observer also found an area on a northerly facing slope where those wind slabs were sitting on a layer of faceted snow. A wind slab would be more reactive to human triggering today, where that slab has developed on a persistent weak layer. The most likely areas to find that layer of faceted snow under these slabs would again be upper elevation northerly facing slopes. 

We can expect more wind loading to occur on Thursday night and into Wednesday, with fresh snow available to transport thanks to the incoming storm. Wind slabs are expected to remain the primary avalanche problem looking ahead to Friday. The potential size and likelihood of this next round of wind slabs will depend on just how much snow we see out of the next storm. The avalanche danger may not jump a full step to CONSIDERABLE, but it will be on the increase. 

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