Early season snowpack tends to always be a little touchy, but this year we are seeing many areas plagued with a very dangerous persistent layer.  Colorado, California, Wyoming and Alaska have all reported a problematic weakness in the snowpack that has triggered avalanches bigger, wider and deeper than expected.

Colorado

As a continental region, Colorado has always had a notoriously unstable snowpack and this year is no exception.  It has been reported that this month alone is the single worst month for avalanches fatalities in the state’s history.  This may come as a surprise since snow totals are at a record low for the month of December but that does not necessarily mean the snowpack is any more stable since it has not snowed.  The snowpack is weak and dangerous plagued with facets to the point where they have now issued an avalanche warning for 9 out of 10 backcountry zones.  If you are backcountry skiing in Colorado make sure you are taking extra precautions and are backcountry savvy to read the terrain and know what is and is not safe to ski or ride. Get the forecast at Colorado Avalanche Center.

So far, December 2020 is one of the worst months for avalanche deaths in Colorado since modern avalanche record-keeping...

Posted by Friends of CAIC on Monday, December 28, 2020

Utah

Utah has a very similar weak snowpack structure that is being seen in Colorado.  A combination of weak faceted layer with a slab 1-3′ deep sitting on top.  Choosing appropriate terrain based on the current snowpack is imperative.  If venturing into the backcountry make sure you choose low angle zones away from steep terrain and avalanche runouts.  For the full forecast check out Utah Avalanche Center.

(12/23/20) HIGH avalanche danger exists on steep slopes facing northwest through southeast above about 9,500' for triggering a slab avalanche 1-3' deep, and traveling in avalanche terrain is NOT recommended. Make sure to the full forecast.

Posted by Utah Avalanche Center on Wednesday, December 23, 2020

Lake Tahoe

The Sierra is generally known for its big snow fall and stable backcountry conditions.  It is not uncommon for the Sierra to go through waves of persistent weak layers but this one seems more touchy than normal and is looking to stick around for longer than normal as well.  Skier triggered avalanches and remotely triggered avalanches have been reported throughout the region.  Avalanches have also gone bigger and ran longer than expected.  If traveling out into the Sierra backcountry, get the forecast and anticipate instabilities in the snowpack by avoiding steep slopes and obvious avalanche paths.  Get the forecast at Sierra Avalanche Center.

12-28-20- We went into the Silver Peak area today to continue to monitor the Dec 11 PWL. A trace to 1-2'' of new snow...

Posted by Sierra Avalanche Center on Monday, December 28, 2020

Tetons

The Tetons have been seeing much more snow than many other areas of the west and are fairing slightly better than other regions. They have a persistent weak layer to worry about that has been triggering large and very large avalanches.   New snow avalanches and wind slabs are a concern as well.   Conservative terrain choices are important when venturing out into the Jackson Hole backcountry.  For the full forecast visit Bridger-Teton Avalanche Center.

Alaska

Alaska started out the season with a deep persistent slab problem, but with heavy snow over the course of the past month, they seemed to have transitioned more into a storm slab/wind slab problem.  They are currently experiencing and upside down storm snow problem where the the snow came in cold and then warmed up throughout the storm.  This weather pattern tends to produce widespread storm slabs.  For a more detailed forecast visit the Chugach National Forest Avalanche Information Center.

If you are traveling into avalanche terrain, make sure you get the forecast, have your avalanche safety gear and the knowledge on how to use it.  We are experiencing a particularly volatile snowpack in much of the Western US.  Choose terrain that is low angle and safe to ride and ski tour through.  We still have a long season ahead of us and hopefully a lot more snow on its way.

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