Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

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

Up to a foot of recent snowfall and efficient winds created sensitive avalanche conditions on drifted terrain.  Soft slab avalanches may be possible in sheltered areas where you encounter around a foot of new snow.  Cracking is a clear sign of a problem in wind-sheltered places.  Avoid terrain that you suspect could be drifted and carefully assess the storm snow in sheltered areas for instabilities.  A less likely, but deadly situation would be to trigger a deep-breaking avalanche on upper-elevation northerly slopes.  Give a wide berth to drifted slopes highlighted by the Persistent Slab problem.

Avalanche problems

  • Persistent Slabs

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

    In the Southeast Mountains, the last round of persistent slab avalanches occurred on March 16th. The most prominent weak layers are surface hoar buried a couple of feet deep and depth hoar near the ground.  The snowfall and windloading may increase the sensitivity of deeply buried weak layers.   Poor snowpack structure still exists in some areas and is commonly associated with a total snowpack height between 80 and 170cm. Persistent slab avalanches can be remotely triggered from low-angle terrain and break deeper and wider than you might expect.   Persistent slab avalanches are unlikely on southerly aspects, or areas where the snowpack is consistently deeper than 200 cm.  Slope angles consistently less than 30 degrees are a reliable way to avoid the problem.

    A large persistent slab on Mt. Crested Butte that ran on 3/16.  This slope is shallow, variable in depth, and on the north half of the compass: a combination of ingredients you want to avoid.  

  • Storm Slabs

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

    Snow totals since Saturday night reach up to a foot with lesser amounts at lower elevations.  The most concerning slopes will be drifted terrain features at upper elevations.  The new snow accumulated above crusts on the south half of the compass and small-grained facets on the north half of the compass.  Avoid terrain where you expect to find drifting.  Carefully assess the recent storm snow in sheltered areas.  You can use small test slopes on wind-protected terrain to investigate for instabilities in the storm snow and how well it bonded to the old snow surface.  Cracking in the new snow is a sure sign of a slab avalanche problem.

    (3/24/2024)

    A triggered avalanche in storm snow on a drifted slope of Mount Emmons.  This avalanche occurred on Sunday; additional snow and wind on Monday will make this problem larger today.

Avalanche Discussion

A slow trickle of snow continues to add volume to storm totals since Saturday night.  Favored locations in the Northwest Mountains exceed a foot with a report of 15 inches in the Antracite Range.  Totals decrease in the Southeast Mountains and are generally less than a foot.

The primary problem in the Northwest Mountains will be managing the recent storm snow.  Expect to find sensitive avalanche conditions where you encounter wind-deposited snow on leeward terrain features.  Observations from Sunday pointed to a developing problem with a triggered avalanche on Mount Emmons, cracking in drifted snow on Anthracite Mesa, and multiple triggered avalanches from the Marble area (1,2,3,4); on Monday triggered avalanches on Axtel and in the Anthracite Range further support an avalanche problem where you find around 1 foot or more of new or windblown snow.  The recent snow fell on a layer of near-surface facets on the north half of the compass, expect conditions to remain sensitive today as a persistent weak layer is responsible for failure below the new snow.  There is uncertainty about the conditions in sheltered terrain, but use caution if you ride in steep, wind-sheltered northerly terrain and carefully assess the storm snow interface.  The storm snow appears to have bonded better where it landed on crusts.

In the Southeast Mountains, there are two problems to manage.  The first is avalanches in the storm snow as mentioned above but there is less storm snow in the Southeast Mountains.  Finding trouble in the storm snow will be more commonly found in drifted terrain and less likely in sheltered areas.  Secondly, the Persistent Slab problem could become more sensitive with the recent loading.  Your best bet is to avoid drifted terrain features highlighted by the Persistent Slab rose as triggering an avalanche that breaks deeply in the snowpack remains possible and would be very dangerous. 

Pay attention to warming snow on sunny slopes if the sun makes an appearance.  Strong, spring-time radiation can quickly heat sunny terrain and cause the new snow to shed from steep sun-exposed slopes.

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