There was a lot of low density snow available for wind transport before this storm, and all the new storm snow came in cold. Storm totals are in the range of 9-12 inches, with wind slabs probably reaching twice that depth. Water content of the storm snow was around 0.6-0.9 inches (Snow Water Equivalent).
Wind was predominately from the East and Southeast at our Turnagain Pass ridgetop stations. Expect the majority of wind loading to be on West aspects with crossloading on North and South.
This cold storm should be compared to the one we got over the weekend. In that storm we had a little more snow, but we saw a number of skier triggered avalanches. We can expect the same today, with possible warning signs like whoomphing (collapsing) and shooting cracks. Conservative decisions are justified today as the snowpack adjusts to the increased stress.
Storm slabs and wind slabs will be the evident surface layers, but the weak interfaces that may fail today could be older and deeper. The freezing rain crust was one of the most reactive weak layers from last weekend. It may show itself again today. Below that rain crust we still have well developed facets on the ground. Fortunately, digging a full depth pit to look at all those layers is easy with our shallow snowpack.
Yesterday temperatures started a dramatic rise. Portage had one weather station increase 56 degrees in the last 24 hours, from -25 F yesterday to 31 F this morning. Ridgetop stations continue to read colder temperatures – less that 20 degrees through the snowfall.
Snowfall and wind are the big news for us today. Mid elevations in Girdwood and Turnagain Pass have about 9 inches of fresh snow overnight. Wind was strong during the snowfall, reaching gusts to 64 mph on Sunburst and 56 mph on Seattle ridge.
The blizzard warning for yesterday has expired, and the snowfall and wind are diminishing. Some clearing this afternoon is expected.
|01/20/21||Turnagain||Observation: Sunburst||Johnston-Bloom / Roberts Forecaster|
|01/19/21||Turnagain||Avalanche: Cornbiscuit||Schauer/ Johnston-Bloom Forecaster|
|01/19/21||Turnagain||Avalanche: Sunburst and Tincan||CNFAIC Staff|
|01/19/21||Turnagain||Avalanche: Seattle Ridge||CNFAIC Staff|
|01/19/21||Turnagain||Avalanche: Tincan 2900′ SW aspect below Hippy Bowl.||Kris Marshall|
|01/18/21||Turnagain||Observation: Turnagain Pass Road Obs.||A Schauer Forecaster|
|01/16/21||Turnagain||Avalanche: Tincan Trees||A Schauer Forecaster|
|01/15/21||Turnagain||Observation: Sunburst||Schauer/ Wunnicke Forecaster|
|01/13/21||Turnagain||Observation: Tincan||Johnston-Bloom / Moderow Forecaster|
|01/13/21||Turnagain||Observation: Center Ridge Meadows||Alaska Avalanche School Rec Level 1 Roberts|
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: firstname.lastname@example.org
|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.