Northwest Mountains

We are less than 36 hours out from the most impressive natural cycle of the season.  Avalanche conditions are clearly dangerous.  Continued windloading or solar warming could trigger more destructive avalanches, some of which have the potential to run nearly full track.  Triggering a deadly slide is likely in steep terrain, especially on the eastern half of the compass.  Avalanches have the potential to be remotely triggered and to break much wider and run further than you might expect.  Conservative terrain selection is paramount today.  You can safely enjoy the powder on slope angles less than 30 degrees that aren't connected to steeper terrain above.  

It's rare that I get to present such clear, undeniable evidence of a dangerous snowpack. Today my job is easy.  Scroll through the gallery below or our observation page, both of which highlight some of the incredible avalanche activity that occurred on Friday night.  The cycle resulted from 4" to 17" of new snow and increased northwest winds on one of the worst snowpack structures our region has seen in quite some time.  We noted some natural avalanche activity continuing into the daylight hours on Saturday; for example, we saw a fresh slide in Red Coon Bowl from Friday night on mid-pack weak layers (the 1/19 layer, presumably) and watched the same path slide AGAIN yesterday afternoon, on basal weak layers (12/10 depth hoar).  That sequence was a first for me and just blows my mind.  Since yesterday's forecast, we've added at least five D3's to the tally.  These are unsurvivable avalanches that snapped trees and piled debris in valley bottom terrain that we don't often recognize as a danger zone.    

Yesterday, a snow safety worker at Irwin was fully buried and successfully rescued while conducting ski checks.  The slope had seen 30 lbs of explosive work the day before including a large airblast.  Yes, our persistent weak layers are surprising all of us, even experts.  Fortunately, no other accidents were reported.  If we zoom out to the statewide scale, there have been four fatalities this week in Colorado. Even worse, since last Sunday, there have been 14 avalanche fatalities across the US.  Much of the West is struggling with the same challenging dry-spell weak layers that are now getting critically loaded.  If the photos below don't illustrate the potential for surprisingly wide propagation and destructive power, some of the recent fatalities should.  In Utah yesterday, 8 people were caught and 4 people killed in a large persistent slab.  Near Silverton earlier this week, 4 people were caught and 3 were buried so deeply it took several days of organized rescue to recover.  I hate to draw attention to these tragic events, but they illustrate the type of accident that could happen in our back yard if we let our guard down.  Avalanches are breaking across entire start zones and even connecting into adjacent start zones in some cases.   

Winds increased last night a few notches higher.  Cinnamon is blowing 30 to 40 mph and gusting into the 60's, while most stations are gusting into the 30's, out of the west to northwest.  With increased winds last night I expect we'll wake up to a handful of more big naturals today.  Strong winds continue today, and the threat of large to very large natural activity continues for windloaded terrain.  I expect we'll see a diminishing trend today as the windward fetches start to run out of snow available for transport or as winds speeds escalate to a point where the snow is sublimating rather than loading.  That's the reason we've lowered the danger to Considerable.   We haven't forgotten about the solar/warming-induced cycle last Sunday.  Today's temps are only expected to reach into the low 20's, and the solar-induced surface warming will be acting on a denser, more consolidated snowpack this time around.  That being said, I wouldn't rule out the potential for more naturals on sunny aspects where the snow surface is warming or where small sluffs get triggered by the sun today.    To boil it down, large naturals are possible today, human triggering on steep slopes is likely.  Avalanches will be large to very large.  Tiptoe through the backcountry with a very conservative mindset to stay out of trouble.

Here's the good news.  There is high-quality powder on a lot of low angle terrain right now. We finally have decent coverage across our whole forecast area.  Thus, opportunities abound for a fun, low-stress day with your friends on slope angles less than 30 degrees while minding your overhead hazards.  Be patient with our snowpack - it is going through some serious growing pains right now.