Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

1 to 2.5 feet of new snow has accumulated since Thursday night, creating dangerous avalanche conditions as new storm slabs have developed, and this load is further straining older persistent weak layers that are capable of producing destructive avalanches. Yesterday, observers at Irwin and in the Slate River Valley reported human triggering many slab avalanches. The riding is going to be very good, but you will absolutely need to control that powder fever with careful terrain selection and cautious route finding.

Avalanche problems

  • Storm Slabs

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

    Soft slabs breaking within the new snow or at the bottom of the new snow will be the most reactive on northerly-facing slopes and in previously wind-loaded terrain. You may not observe obvious signs of instability until you get into steep or suspect terrain. Consider choosing southerly facing slopes over northerly facing slopes, and further manage this avalanche problem through your slope angle choices. On northerly facing slopes, a triggered storm slab could step down into a much larger persistent slab avalanche. 

    A pile of human-triggered avalanches in the Slate River Valley on Friday. 

  • Persistent Slabs

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

    Dangerous slab avalanche can be triggered on facets or depth hoar layers in the middle or bottom of the snowpack.  Persistent or deep persistent slab avalanches are most likely to be triggered on the northern half of the compass and where the snowpack is unusually thin and weak.  In rare cases, they might also be triggered on deeper slopes from step-down avalanches in the upper snowpack or cornice falls. Be cautious of very steep, rocky, or wind-affected terrain with variable snow depths and slopes receiving heavy windloading today.   Southerly slopes generally lack the problem due to previous meltwater strengthening the snowpack.  You can avoid the problem on slope angles consistently less than 30 degrees.   

    Avalanches could easily run into lower angled slopes below steeper slopes like this large avalanche that ran in the last couple of weeks.

Avalanche Discussion

Avalanche conditions are notably different between the NW Mountain and SE Mountain forecast areas. Dangerous avalanche conditions are more widespread in the NW Mountains, while they are more specifically located in the SE Mountains. This is due to the dramatic difference in the recent snow accumulations between the two areas. 1.5 to 2" of SWE has accumulated in the NW Mountains, while the SE Mountains received an average of .5 SWE or less with a few outliers. That new snow was further accompanied by strong westerly winds.

Give the weekly summary a read for more details on the current snowpack and avalanche conditions heading into the weekend. You can view the video summary here, or the text summary here. 

Looking ahead, we have two notable weather factors that will continue to influence avalanche conditions. Wind speeds start picking back up later this afternoon and remain elevated into Sunday. Those winds will continue to load the lee sides of terrain features and hold the potential for continued natural avalanche activity. The other weather factor influencing avalanche activity will be when the March sun makes an appearance and puts wet avalanche activity back on the menu. High temperatures remain cool on Sunday, but with a clearing sky, we can expect another round of wet avalanche activity to begin. 

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