Bulletin d’avalanche

Southeast Mountains

Crested Butte Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Yesterday, a large slab avalanche was triggered on Schuylkill Ridge and over the weekend, a snowboarder was caught and partially buried when he triggered an avalanche from below the slope.  These examples highlight the persistent instabilities that remain a serious threat on the northern half of the compass.  Northwest winds increased yesterday afternoon, forming a fresh batch of wind slabs behind leeward terrain.    Use extra caution on shadier aspects or where you see signs of fresh drifting.  Collapses and shooting cracks are clear warning signs to choose mellower terrain.  Southerly facing terrain protected from the wind offers the least hazardous snowpack right now. 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5

    On the northern half of the compass, you can trigger a dangerous slab avalanche that breaks 1 to 3 feet thick on weak faceted snow buried last month.  Slabs can be triggered remotely from below or adjacent slopes.  Collapsing and cracking are clear signs of instability, although feedback on this problem is becoming more variable.  For example, a skier on Monday triggered a large slab avalanche on Schuylkill Ridge after reporting no signs of instability all day.  Use extra caution and choose more conservative terrain on slopes that face northwest to east.   

    This persistent slab caught and partially buried a snowboarder last weekend on a northeast aspect below treeline. The snowboarder triggered the avalanche from below the slope while he was hiking uphill.  

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Fresh slabs of drifted snow are forming below ridgelines and in cross drifted terrain features.  Winds shifted to the northwest yesterday afternoon and could increase later today.  The shifting winds found plenty of loose snow to work with; observers noted blowing snow at higher elevations late in the day.     Look for and avoid steep slopes with obvious drifts.  Drifted snow will feel denser and look deeper compared to wind-sheltered snow.  Cracking under your skis or blowing snow are signs of instability.  

    Northwest winds were visibly transporting snow into Red Lady Bowl yesterday afternoon.  

Avalanche Discussion

The weekend storm brought an impressive amount of snow ranging from 15" to 30", favoring the Northwest Mountains.  The snow came without as much water weight and wind as we often see with these larger storms.   Our observations over the past few days suggest that natural activity remained relatively quiet throughout. With only a few triggered persistent slabs during the loading event, we are cautiously lowering the danger now that the loading period has ended.  Tomorrow, the danger will ramp back up through the day and overnight as another wave of heavy snowfall with stronger winds pushes through the region.  Today, human triggering is a very real possibility.  

Yesterday afternoon, we saw a shift to northwest winds, which ignited wind transportation in some terrain.  Expect to encounter fresh slab formation behind leeward features favored by northwest winds and monitor for additional transport today if winds increase this afternoon.  

Yesterday, a forecaster intentionally triggered a large avalanche that failed on a faceted bed surface left behind by the last cycle.  This is the first "repeat offender" slide we've seen so far.  While many of our bedsurfaces from the last cycle have remained quiet throughout the last storm, this might be the canary in the coal mine suggesting we'll see more repeat offenders with Wednesday's loading event.   Faceted bed surfaces are widespread after our last cycle, and slabs in them are just starting to rebuild.  Steep slopes on northerly aspects that didn't avalanche during the last cycle have thicker and more dangerous slabs on these same facet layers right now.  Either way, you can avoid dealing with these persistent slab issues by traveling on southerly aspects today.  Warm temperatures and meltwater last week reduced the threat of persistent slabs on those southerly aspects, so any instabilities will be confined to the recent and drifted snow.  

Régions couvertes