Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

The avalanche danger will rise through the day and overnight as snow and winds form storm instabilities and stresses buried weak layers.  Fresh slabs will develop first at higher elevations, where winds are drifting the new snow.  You can also trigger an avalanche that breaks deeper than the new snow, most commonly on drifted slopes or where the snowpack is unusually shallow.  Monitor snowfall accumulations and choose more conservative terrain free of terrain traps if snow totals exceed about 10".  

Avalanche problems

  • Persistent Slabs

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

    There are faceted weak layers in the middle and bottom of the snowpack that remain a concern in some terrain.  The most concerning slopes include those that held an unusually shallow and weak snowpack prior to last weekend's storm, where snow depths are currently less than about 5 feet deep, or wind-drifted terrain with variable snow depths.  Recent "step-down" avalanches in West Brush Creek and East Brush Creek highlight the potential for avalanches to break on deeper weak layers in the Southeast Mountains.    Carefully assess the snowpack structure and give yourself a margin for error in handling this problem. There is a high degree of variability across the region and on different aspects.

    Debris from a very large persistent slab that ran off of Teo during the last storm, around 3/11.  

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Fresh slabs will become sensitive to triggers as new and windblown snow thickens throughout the day.   Slabs should remain relatively small today in most terrain, but could grow large in size on a few leeward terrain features with long-running terrain by day's end.  Monitor new snow accumulations and look for signs of instability such as cracking or blowing snow before riding in steep terrain.  Shallow slabs can cause trouble if they push you into trees or gullies.     

    Look for cracking like this to identify changing avalanche conditions and developing storm slabs. 

Avalanche Discussion

NW Mountains:  It's a straightforward day of new snow management.   Following yesterday's warmup and overnight refreeze, most surfaces are crusty with some dry powder remaining on northerly slopes.  Avalanches breaking below this morning's storm interface are unlikely.  Expect poor bonding of the new snow to yesterday's crusts. The danger strictly depends on how much snow we get today.  The danger is Low early this morning, and will rise towards Considerable sometime later this afternoon or evening, depending on how much and how quickly the new snow piles up.  Slabs will be thicker and more sensitive at higher elevations where snow accumulations will be deeper and winds will be stiffening the new snow.   Use small test slopes to get a feel for the size and sensitivity of new snow instabilities.  If today's storm totals significantly exceed our snow forecast, expect the danger to rise to Considerable at mid and lower elevations as well.  

SE Mountains:  It's the same new snow considerations, but with additional concerns for avalanches to break on deeper weak layers.  Storm totals look to be less today in the Southeast Mountains, so we're not expecting new storm slabs to be as common or large by sunset.  During last weekend's storm, we saw several large to very large avalanches break on old weak layers.  We are most concerned about human triggering in terrain that holds unusually shallow snow depths or drifted slopes with variable snow depths.   The warm, sunny weather over the last two days formed thick crusts on the southern quadrant which has strengthened the upper snowpack and reduced the threat of triggering a deeper avalanche on those aspects.  The avalanche danger is Moderate this morning and expected to rise to Considerable sometime tonight as storm totals increase.  If storm totals significantly exceed our snow forecast, expect the danger to rise to Considerable before sunset.   

Events:  The Al Johnson race is Sunday, March 19. Information and registration are here.  Day of race registration and bib pick up 9-11 a.m. at the Adventure Center in Mountaineer Square. Proceeds go to the CBAC.

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