Wind slab avalanches will be the most concerning avalanche problem today. With storm totals upwards of 15-18″ these are expected to be 1-2+’ deep, soft and potentially quite sensitive to human triggers. They are most likely to be found on slopes over 35 degrees just off ridgelines, on rollovers and the side-walls of gullies. Keep an eye out for any slope with signs of recent wind loading – this means areas with stiffer snow over weaker snow, smooth rounded surfaces and hollow feeling snow.
Though the wind died down in most locations yesterday afternoon, it was blowing moderately to strong from the east early in the day yesterday. Though any natural activity has likely ceased, I’m expecting there are some good sized wind slabs that are still fresh enough to cause problems for people. If the visibility breaks enough for travel to the more exposed terrain, finding a 2’ deep unmanageable wind slab is not out of the question.
Below is a poor image of a few small wind slab avalanches on Tincan yesterday (human triggered 2,500′, W aspect). It is still uncertain how the upper elevation wind affected slopes are handling this new load. More on yesterday HERE and HERE.
How is the early December crust behaving?
The new snow did fall on a ~¼” breakable crust which had, in places, surface hoar on top. Though this interface was showing a fairly good bond yesterday, I would not count out that avalanches could be larger and run further with this crust providing a slippery bed surface and the added uncertainty of the now buried surface hoar.
It will be mostly a sluff management day. With decreasing temperature and generally calm to light winds, much of the new snow will be in a very loose unconsolidated state (‘cold smoke’?) and initiating a loose snow avalanche will be likely. In continuously steep, channeled terrain expect sluffs to gain in volume, run fairly far and become more of a concern.
24-hour snowfall totals (6am Saturday to 6am Sunday):
Storm totals are (8am Friday to 6am Sunday €“ past 46 hours):
Currently, light snowfall continues in the Eastern Turnagain Arm which may add another inch this morning. The easterly wind that averaged 20-30mph with gusts to the 50’s yesterday morning has decreased to the 5-10mph range and backed to the north. Temperature has dropped from the 20’s to the single digits overnight.
Today, skies should slowly break and snow showers taper off as the low pressure over us heads east and colder drier air moves in. Wind looks to remain light, 5mph, from the north and temperature remain in the single digits to low teens at most locations.
Tomorrow and Tuesday look to be clear and cold before another system moves in Wednesday/Thursday. It looks like winter is arriving!
|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.