Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sun
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Very dangerous avalanche conditions exist and an Avalanche Warning is in effect.  A potent storm quickly deposited 2 feet of snow with strong southwest-to-west winds.  Expect to very easily trigger avalanches in the storm snow, natural avalanches may occur, and some avalanches could break deeply into the snowpack on old weak layers.  Travel in avalanche terrain is not recommended.  If you travel through the backcountry today, take the time to select routes that allow you to avoid being on or below slopes greater than about 30 degrees. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–2.5

    Storm totals are roughly 2 feet around the forecast area from only a 24-hour period and additional snowfall is forecasted for Saturday.  Snow densities are well above average for the area.  Temperatures were colder at the beginning of the storm Friday morning and warmed throughout Friday and remained warmer overnight.  With impressive, dense storm totals, rapid loading, and warming temperatures through the storm expect human-triggered avalanches to be very likely.  Avalanche size will commonly be large enough to bury, injure, and kill you.  Natural avalanche activity will be most likely during periods of high-intensity snowfall and wind-loading.

    A Storm Slab avalanche in a sheltered area from a previous storm.  Expect natural and human-triggered avalanches to be twice as deep as the one pictured here.

  • Persistent Slabs

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

    The current storm cycle could potentially awaken deeper weak layers in the snowpack.  Avalanches that break into weak layers in the middle or bottom of the snowpack would grow to dangerous sizes and be difficult to survive.  Uncertainty exists about whether or not deeper weak layers will re-activate during this storm.  The picture will become clear once the skies open up and more observations can be made.  With dangerous conditions with storm snow instabilities, it is easy to simply avoid travel in or below avalanche terrain to manage the potential for avalanches to break deeply in the snowpack. 

    A large persistent slab that ran over the past weekend. Outside of the forecast area near Ashcroft.

Avalanche Discussion

Storm totals, high water equivalent snow, and strong southwest-to-west winds have created very dangerous avalanche conditions.  It is uncommon for our area to accumulate 2 feet or more of high water content snow in a 24-hour period and for temperatures to warm during the storm.  You can be confident that drifted, leeward terrain is very dangerous today and that human-triggered avalanches are very likely where the wind drifts the snow and that avalanches in the storm snow will be more than large enough to bury and kill you.  Natural avalanches will be likely on slopes that are loaded today by westerly winds.

Sheltered areas will be dangerous as human-triggered avalanches will be very likely in the storm snow and storm volumes in sheltered are plenty deep to bury you.  Some uncertainty exists about how widespread natural avalanche activity will be in areas that are protected from the wind.  Periods of heavy snowfall could spur a round of natural avalanche activity during the day as pulses of moisture move through the area.  Even if there is not a widespread natural avalanche cycle below treeline today, avalanche terrain at low elevations is dangerous and should be avoided.

Most avalanche activity is expected to involve just the storm snow, but there are some areas in the Southeast Mountains where avalanche activity may involve weak layers deeper in the snowpack.  Areas in the Southeast Mountains where the snowpack is shallower could break deeper in the snowpack.  Terrain close to the valley bottom near Crested Butte, the lower East River, lower Brush Creek, and lower Cement Creeks may produce avalanches that break deep into the snowpack on weak layers that formed earlier this winter.

If you choose to travel through the backcountry, simply avoid exposing yourself to avalanche terrain.

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