Lawinenlagebericht

Southeast Mountains

Crested Butte Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Impressive southwest winds and around a foot of snowfall are creating dangerous conditions.  Drifted slopes at upper elevations are the most dangerous places although yesterday's extreme winds drifted snow at lower elevations as well.  Some avalanches in drifted terrain could break into deeper weak layers beneath the recent storm snow.  Avoid drifted terrain and use caution in sheltered locations by observing the bonding between the new and old snow.  Shooting cracks and collapses are clear signs of unstable conditions.  Natural avalanche activity is possible where wind-loading occurs. 

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1.5–2

    Storm slabs will be likely to human triggers or they may release naturally on wind-loaded terrain; simply avoid wind-drifted slopes.  In wind-sheltered terrain, there is uncertainty as to how reactive this avalanche problem will be. While in wind-sheltered areas look for small, steep test slopes to help identify how reactive Storm Slabs are in the area you are traveling.  

    Blowing snow is creating the largest and most reactive avalanche conditions on wind-loaded terrain features. 

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–2.5

    Over the past 2 weeks, several large avalanches have failed on faceted weak layers deeper in the snowpack.  These include a natural avalanche on Carbonate Hil on Thursday, a remotely triggered avalanche on Mt. Emmons on Sunday, and several human-triggered slides the previous week (Hunter Hill, Snowmass). Persistent slab activity has been infrequent this month and most problematic on wind-loaded terrain.  The current loading event will stress buried weak layers and the expectation is for this avalanche problem to become more reactive again. Traveling on lower-angled slopes without overhead hazards is the safest method to manage this avalanche problem. 

    A large persistent slab avalanche that was human triggered earlier this month. 

Avalanche Discussion

Mother nature delivered up to 2 feet of snow in the Northwest Mountains and around a foot of snow in the Southeast Mountains accompanied by strong to extreme southwest winds.  The meteorological evidence and human-triggered avalanches from Wednesday (Schuylkill Ridge, Climax Chutes) clearly point to dangerous avalanche conditions on drifted terrain.  More snowfall and southwest winds today will keep the pressure on drifted terrain and add more fuel to the dangerous conditions.  Drifted slopes in the Southeast Mountains have the distinct possibility of breaking in old snow deeper in the snowpack and becoming larger and wider than expected.    Given the strength of recent winds, do not be surprised to find some drifted terrain features below treeline. 

Sheltered terrain presents some uncertainty.  Storm totals in the Northwest Mountains are deep enough to be dangerous in sheltered areas and less dangerous in the Southeast Mountains as storm totals are roughly half.  Take the time to look for signs of instability, test the bonding between the old/new snow interface to better understand how it is bonding.  This avalanche in a sheltered location on Schuylkill Ridge is a good example of the potential poor bonding between the storm snow and the old surface or this observation of shooting cracks on Snodgrass.

The upper snowpack on easterly and westerly slopes contains several facet/crust layers that could become reactive during this stormy period.  A test profile from an easterly slope on Schuylkill Ridge did not look to have enough recent storm snow to cause an issue, but areas with more snow from drifting may be getting closer like this surprise remotely-triggered avalanche from Mount Emmons immediately before the storm.  Collapsing is a clear sign those crusts have reached a tipping point.  You can quickly dig down and test these layers of concern as they are only a few feet below the surface.

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