Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

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

An AVALANCHE WATCH is in effect; stay alert for rapidly changing conditions.  The avalanche danger will rise to HIGH overnight and a large natural cycle is expected to continue through tomorrow.  During the daylight hours today,  warm temperatures and strong winds are increasing the threat of large cornice falls and natural avalanches from high-elevation, windloaded terrain.  At any elevation, you can trigger a dangerous slab avalanche on west, north, or east facing terrain steeper than about 35 degrees over weak layers buried 1 to 2 feet deep.  This close call with a large avalanche yesterday illustrates the threat.  The safest riding is on southerly facing terrain sheltered from the wind, or lower slope angles free of overhead hazards elsewhere.   

 

Avalanche problems

  • Wind Slabs

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

    A few inches of new snow today and strong winds are forming shallow, sensitive drifts on leeward slopes at higher elevations.  Today's wind slabs could cause harm in high consequence terrain, or if they step down and trigger a larger persistent slab.  Look for blowing snow and thicker, dense feeling snow below ridgelines and in crossloaded gullies to identify the problem. Travel in wind sheltered terrain to avoid today's wind slabs.  

    A wind slab photo from the archives.  

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    A new round of weak layers was buried on February 2nd. These weak layers consist of widespread surface hoar and facets on most east, north, and west-facing slopes, and along with some faceted crusts on higher elevation southerly aspects. Slabs about 1 to 2 feet thick over these weak layers are becoming more stubborn, but can still be triggered by skiers and riders. This avalanche problem can be remotely triggered from flat terrain, or may propagate further than expected.  Shooting cracks or collapses are a clear sign of danger, but these obvious signs of instability will not always show themselves before an avalanche releases.  There is isolated potential to trigger older, larger slabs on weak layers deeper in the snowpack, most likely from shallow terrain features or step-down avalanches.  

    You can reliably avoid trouble on terrain with slope angles less than 30 degrees that are free from overhead steep terrain. Lower elevation southerly aspects offer safer options for steep terrain.  

     

    This avalanche appears to have been remotely triggered, or ran naturally, in Red Lady Gades on Friday. 

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Strong winds and warm temperatures are increasing the threat of natural cornice falls today, similar to the cornice fall activity that occurred during last week's warm and windy storm.  Cornice falls are triggering large slab avalanches on some slopes, producing larger and farther running debris than you might expect.  Avoid traveling below corniced ridgelines today.  

    Several large cornice falls and subsequent slab avalanches below a corniced ridgeline in Redwell Basin. These ran during the warm, windy storm last week.

    Photo: Zach Guy

Avalanche Discussion

Intense snowfall and strong to extreme winds tonight and tomorrow will likely spur a significant avalanche cycle in the next 36 hours.  The most recent weather models are delaying the onset of heavy snowfall until about midnight, with only a few inches of snow expected during the daylight hours today.  Thus, today's danger ratings have backed off compared to yesterday's forecast.   Fear not, the storm is coming and we're all hoping this is going to be the surface hoar flusher and crusher that our snowpack needs.   During the daylight hours today, the danger will start increasing at higher elevations due to increasing wind transport from strong winds and a few inches of new snow available for transport.  This will form fresh wind slabs, trigger more cornice falls, and add stress to our persistent slab problem which has been active all month.   Monitor snowfall accumulations for more snowfall than we are forecasting for today, and adjust travel plans accordingly if it starts hitting hard before sunset.  

Yesterday's close call on Double Top exemplifies our primary concern today.  I really appreciate the reporting party's willingness to share their insightful story: read their account here.  Our persistent slab problem has been a really challenging issue this month, we've seen triggered or natural activity almost every day in February.  Our forecast team yesterday in the Beckwith Range found all the ingredients for surprising backcountry travelers.  The troublesome surface hoar layer was absent in our first pit and we saw no signs of instability all day because the slabs are stiff enough that we aren't easily affecting the weak layer.  However, our second pit showed a frighteningly weak surface hoar layer, still perfectly intact and standing tall below a 80 cm hard slab.  It might take crossing a shallower spot, or steep convexity, or traveling in a more snow-starved area where slabs are thinner, but the problem is still alive and well out there.  This coming storm will certainly produce avalanches on our February weak layers, and we might see our early season weak layers come to life too.  

Events: The CBAC Fireside Chat Series presents legendary American alpine climber George Lowe on Sunday, March 3 at the Mallardi Cabaret Theatre in downtown Crested Butte at 6 p.m. Best of all, it’s free!

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