Northern New Mexico

You can trigger a persistent slab avalanche at all elevations and on most aspects today.  Cohesive slabs of snow sit on top of weak and faceted snow deeper down in the snowpack or on the ground. Red flags like loud audible collapses and shooting cracks are becoming more isolated and may not give you the warning signs we've been seeing over the last couple of weeks.  It's still possible to remotely trigger avalanches above you from the flats below, so give steep terrain wide berths. Any avalanche triggered could be large enough to bury you, potentially failing on or near the ground.  Sticking to lower-angle wind-sheltered terrain will provide safer skiing and riding options. 

If you've been following the forecast over the last couple of weeks, you'll know that avalanche danger has been elevated (Considerable or High) since January 4th as storms and wind events have loaded slopes and created cohesive slabs on top of a fragile snowpack that existed before these January storms.  Over this period we've seen lots of avalanche activity from natural to human-triggered avalanches at all elevations on west through north to southeast aspects.  It's now been 8 days since our last snow event as storms have tracked to our north in CO, and moderate to strong winds have calmed down starting on the 18th. An inch or two of snow today is not going to be enough to increase the danger. 

We've dropped the avalanche danger to Moderate at all elevations today as human-triggered avalanches are possible and natural avalanches are unlikely. This process has been slow for us, which speaks to how fragile and weak persistent weak layers are deeper in the snowpack as they adjusted to loading earlier in January. In travels over the last couple of days, loud audible collapses and shooting cracks have become more isolated and we haven't been seeing new natural avalanche activity.  In long-column stability tests, it takes moderate force to get deeper weak layers to collapse and propagate across the column.  And explosive control work over the last couple of days has produced limited results in uncompacted terrain near and below treeline. Transitioning to moderate does not mean the persistent slab avalanche problem has gone away but conditions are not as sensitive as what they have been. In terms of moderate avalanche danger, we are definitely on the higher end of that spectrum.  Whether you want to call it a "scary" or a "spooky" moderate I like to think of it as a lower likelihood of triggering an avalanche but the consequences remain high if you were to trigger one. This tends to be when accidents happen, as we start slowly stepping out and feeling more comfortable traveling in avalanche terrain.   

The main concern continues to be persistent slab avalanches with avalanches failing on weak faceted snow that formed on the surface or around crusts during the end of December and early January dry period or on depth hoar near the ground. These weak layers are widespread and everywhere across all elevations and most aspects.  What does change in the snowpack structure is the overlying slab on top.

Below treeline, the slabs have been settling ( 10" over the last week at Poco Wx Station) and stiffening into more cohesive slabs.  Weak layers at these lower elevations are still very easy to impact and in travels, we're still getting collapsing which is becoming more isolated. Conditions are not as hare-trigger as they were a couple of days ago as we push further away from the last loading event, but any avalanche triggered is likely to fail on or near the ground on depth hoar, taking with it most of the season's snowpack.  Triggering avalanches has become more stubborn but still possible if you find the right slab/weak layer combination below treeline.  

In above treeline terrain, moderate to strong winds over the last week have stripped and scoured some slopes at upper elevations and loaded and pressed other slopes into harder slabs, with breakable wind crusts on others. You may find and be able to trigger shallow stubborn wind slabs on northerly and east aspects above treeline but the bigger concern continues to be triggering a larger persistent slab avalanche.  With thicker and stiffer slabs, it may take finding that "sweet spot" on the margins of the slab or near rock outcroppings where the overlying slab is thinner.  It also may not be the first person on the slope to trigger an avalanche and hard slabs can break in unpredictable ways, oftentimes well above you.  Signs of instability like audible collapses and shooting, will more than likely not be evident and give you a false sense of security until it's too late.  Avalanches at upper elevations will be large and may not be survivable.     

Near-treeline terrain is a transition zone where conditions are mixed between the below and above-treeline terrain.  Weak layers deeper down in the snowpack and near the ground are still easily within impact zones across slopes and winds earlier in the week have loaded slopes into more cohesive slabs, but not the hard slabs we're finding above treeline. East-facing, near treeline terrain, seems to be the sweet spot for recent avalanche activity over the last week.     

Unfortunately, this persistent slab problem is going to be with us for a while.  With more snow potentially impacting us later in the week, we'll have to see how it comes in.  A more gradual loading trend will help these weak layers adjust to the new load.  If we do see bigger storms, expect avalanche danger to ramp back up.  In the meantime, there is still great skiing and riding to be had, especially in wind-sheltered lower-angle terrain.