Southeast Mountains

A Special Avalanche Bulletin is in effect through the weekend for the Southeast Mountains.  Our fragile snowpack is coming off of a week-long loading period that produced hundreds of natural and triggered avalanches.  Although the natural cycle is generally over, large and dangerous avalanches are sensitive to human triggers on almost all aspects and elevations on terrain features that didn't recently avalanche.  Bring a conservative mindset into the backcountry this weekend.  Even low-elevation slopes near Crested Butte, Mt. CB, and CB South are dangerous right now.  

Observers yesterday reported numerous natural persistent slabs that ran yesterday in the Southeast Mountains, and limited alpine visibility in the Northwest Mountains.  The most notable of these avalanches was a slab in West Brush Creek that connected across two start zones and broke 5 feet deep on very weak depth hoar at the ground. Check out this video for some cool footage of the slide.  Now that the loading period is over, the natural cycle is expected to be largely done.  We could still see a few naturals run today or tomorrow from warming-related releases, or step downs from solar-induced sluffs. 

A Special Avalanche Bulletin has been issued for the Southeast Mountains, where large slab avalanches are especially sensitive to human triggers right now.  Some of the worst conditions are at lower elevations near urban areas or in the adjacent drainages.  That's because slabs are still an ideal thickness for human triggering, and the snowpack was incredibly weak and shallow in these areas before our January storms.  This observation from the Aspen side represents what I would expect to find in parts of Cement Creek or Lower Brush Creek, etc.   We've been finding that the persistent slab is becoming more stubborn to human triggers in deeper snowpacks now.  Lower likelihood, yes, but the Catch-22 is an unsurvivable size.  In some cases, the weak layers aren't as bad and gaining strength now, but in some cases, the fewer signs of instability are simply because slabs are so thick that your weight isn't affecting the treacherous weak layer.  Don't be fooled; there are often shallow deficit zones even where the snowpack is deep.  Irwin continues to report isolated collapses and explosive results.  Shallow trigger points are most often associated with wind effects; slabs are more variable in thickness in wind-drifted terrain.  They can also form near trees or rock bands in wind-protected terrain.  Right after the end of a loading period, it's a bit of a gamble to hope you don't find a hidden shallow spot; those deeper slopes will be improving and strengthening in the days ahead.  For now,  the more reliable tactics are using slope angles for avoidance or riding on steep slopes where the problem recently avalanched away.  

Yesterday, a Crested Butte resident was injured by a roof avalanche.   Roof avalanches are most common when temperatures rise above freezing, which we are expecting in the next two days.  Be mindful of what's above you and be a helicopter parent if you see evidence of roof avalanche activity starting to happen.