Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
View on map

Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

An Avalanche Watch is in effect today.  Heavy snowfall will dramatically increase the avalanche danger over the next 24 hours, and the danger is expected to reach HIGH tonight.  Avalanches will be easy to trigger and grow to dangerous sizes as storm totals increase.  Natural avalanche activity will increase through the day and overnight.   Monitor storm totals and choose more conservative terrain as the storm progresses.  Travel in and below avalanche terrain (slopes steeper than 30 degrees) is not recommended tonight. 

Avalanche problems

  • Persistent Slabs

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

    Heavy snowfall and wind loading will quickly build slabs up to several feet thick over the multitude of facet layers in our shallow, weak snowpack.  Slabs will increase in size and sensitivity through the day, becoming easy to trigger by sun down.  As the slabs thicken, expect avalanche behavior to become more challenging, with wider propagation, remote triggering, and natural releases.  This challenging persistent slab behavior will develop first at upper elevations and move to lower elevations as storm totals increase towards 2 feet.  The most problematic slopes face west, north, and east: avoid traveling on or under steep slopes on these aspects to manage the problem.  

    This photo is from a previous season but illustrates avalanche activity we expect to see in the coming days.  

  • Storm Slabs

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

    With heavy snowfall rates producing over a foot of snow today, storm instabilities will develop within the storm snow and at the storm interface.  Even on slopes without well-developed persistent weak layers, you will need to manage storm slab instabilities by monitoring storm totals and looking for feedback on small test slopes.  Storm slabs will also grow in size throughout the day; choose more conservative terrain and smaller slopes as the day progresses.  Low elevation, southerly slopes that were bare at the start of the storm will offer safer travel today.  

    An example of a storm slab on a small test slope.  

Avalanche Discussion

Over the next 24 hours, a major winter storm will overload our early-season snowpack, causing a significant natural cycle.  For details on expected storm totals, head to our weather forecast tab.  Avalanches will begin running naturally today, and become larger and more widespread as storm totals increase.  Our threshold for going to High Danger is around 2 feet of new snow, and we expect the Northwest Mountains to get there by sunset, with the Southeast Mountains following suit overnight.  We'll be at Considerable danger most of the day today, and you'll find problems are smaller and easier to manage earlier in the day.  By later today and tonight, many avalanches will be large enough to bury or kill you (D2).  

Our shallow snowpack consists of multiple layers of facets and faceted crusts on west, north, and east aspects (see these obs: 1,2,3, 4), that will not tolerate our intense storm.  Yesterday, we saw a tiny preview of what's to come with a large avalanche on the east face of Gothic and a remotely triggered slide 3 feet deep on Baldy.  Alpine slopes like these will be the first to develop large and thick slabs that propagate across terrain features, whether they break on faceted snow near the storm interface or on older layers deeper in the pack.  At lower elevations on shadier aspects, the snowpack is entirely faceted below the new snow: slides will gain volume and entrain old snow once they start running.  As slabs thicken below treeline over the next 24 hours, management strategies will change from easier storm slab to more challenging persistent slab behavior with remote triggering and slides connecting across terrain features.    The slopes offering the safest travel and easiest management will be on low elevation southerlies because these slopes were bare before the storm, lacking any persistent weak layers.  

Regions covered