Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, December 4th at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).
The avalanche danger is HIGH for the Turnagain Pass, Summit Lake and Girdwood Valley today. Strong winds, new snow and rain, have dramatically increased the potential for naturally occurring avalanches. Below treeline, wet snow avalanches will be likely due to rain on snow. Above treeline, wind slab and soft slab avalanches will be likely due to the recent, and ongoing, new snow and strong wind. Travel in avalanche terrain, including runout zones, is not recommended today.
Yesterday, we had a couple reports of small wind slab and soft slab avalanches in the Turnagain Pass area. More details are on our photos/observations page.
The cold and dry snow we have been enjoying for the past several weeks is currently being washed away by a warm storm that hit our region yesterday. Overnight, rain on snow impacted areas below 2000′ while around a foot of snow has accumulated above. Winds have been adding to the mess and are gusting to 60mph. Today may be a good day to get a start on Christmas shopping as this weather continues.
Areas below 2000′
Rain on snow overnight, which is forecast to continue throughout the day, has saturated the snowpack in the mid to lower elevations. This is the first time the 3-4 foot pack has seen rain and above freezing temperatures. This is a good set up for wet snow avalanches. These are likely to release naturally (on their own) today. Steering clear of all steep slopes, and their runout zones, is advised.
Areas above 2000′
Storm snow and wind slab natural avalanches are likely. All locations above 2500′ have received, what looks like, around a foot (or more) of snow overnight with anCNFAIC Staff 8-12″ forecast for today. The winds are STRONG, gusting to 60mph on the ridges, and loading slopes quickly.
With the variety of avalanche problems today, all of these have the potential to break out wider and deeper due to weak faceted snow that is sitting in the middle of the pack. Though this weak layer has been stubborn in our pit tests, it has not been tested yet by new snow/rain and deserves respect.
Only a few inches of snow fell yesterday before the brunt of the storm finally moved in later in the afternoon. Overnight, 5″ of wet snow fell at the Tunagain Pass SNOTEL site with 0.9″ of water weight. Girdwood valley has seen slightly more. These numbers are for ~1900′ where the snow switched to rain early this morning. Currently, the rain snow line is hovering just under 2000′, but expect it to increase to just above 2000′ today. Temperatures are 35F at 1900′ and 28F at 3200′. Winds are gusting to 60+mph on the ridges. More rain, snow and wind are on tap today. AnCNFAIC Staff 8-10″, and possibly more in favored areas, is expected at the higher elevations. Temperatures will remain warm, above freezing at 2500′, and winds are forecast to remain strong as well, gusting in the 60mph range.
For those doing some Christmas shopping: A great way to help support the avalanche center is by purchasing items through the links on the right side of our website (Patagonia, REI, etc). We get a percentage so check it out!
I will issue the next advisory tomorrow morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.