We found a big piece of the puzzle yesterday in the form of recent natural avalanches. The presence of naturals underscores the seriousness of the current snowpack. Sugary faceted snow crystals form the foundation of our snowpack everywhere right now. They are showing a tendency to collapse when stressed and will avalanche on steeper slopes.
Turnagain Pass got a small amount of snow on Sunday, which probably added enough stress to cause the avalanche in the picture below. This is a steep north facing slope on Seattle ridge, and is representative of most of the region. Similar problems have been found near Portage, Summit, and Eagle River.
The cold weather combined with such a shallow snowpack is transforming all the snow into weaker faceted crystals. We are finding a strong temperature gradient everywhere which is made worse by sub-zero temperatures. In most places you won’t find much of a stiffer slab on top of the weaker snow. This lack of a slab is preventing a lot of slopes from avalanching for the time being. When we do get stiffer snow and more stress on top of the delicate foundation, avalanches will be much more likely and dangerous.
Wind overnight hit gusts to 30mph at ridge tops. This is the strongest wind we’ve had in over a week. If the wind was strong enough to transport the loose surface snow, we could have enough slab to cause problems. Any stronger or denser snow on top of the super weak facets near the ground is likely to exacerbate our problems.
Wind overnight is the big news since yesterday. The last snowfall is now several days in the past, but was enough to cause some snow stability problems in the form of natural avalanches. The storm hitting Southeast Alaska today is not expected to have a significant effect on Southcentral. A slight chance of snow showers is possible today. Wind is expected to increase in some areas this afternoon.
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer Forecaster|
|04/12/21||Turnagain||Observation: Tincan||Johnston-Bloom / Latosuo Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: email@example.com
|Area||Status||Weather & Riding Conditions|
This is 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.