|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
Finding and triggering a slab avalanche that breaks in weak snow 1-2+’ deep in the pack remains a concern. This could be in the form of a lingering wind slab or a much older slab that sits on weak layers in the mid-pack. Although today’s clear skies should reveal a dusting of new snow from yesterday, this is likely only enough to obscure a generally variable and wind affected surface through the region. With a longer sunny day ahead, here are the things to keep in mind:
Lingering wind slabs: Strong Northwest winds impacted the region last week and due to unusual wind loading patterns, formed hard wind slabs on a variety of aspects. Watch for steep areas harboring stiff snow over softer snow and cracks that shoot out from you. Old wind slabs can be found along ridgelines and in steep rocky terrain, but also mid-slope in cross-loaded gullies. Even a small slab can have high consequences in steep and committing terrain.
Persistent slabs: Several weak layers sit in the middle and base of the snowpack and as recent as last Tuesday, skiers triggered a large ‘persistent slab’ in the Summit Lake area. This problem has shown to be more pronounced on the Southern end of Turnagain Pass and Summit Lake where the snowpack is shallower (areas to the North, such as Crow Pass, could also be suspect). Wednesday, during the wind event, numerous large avalanches released naturally near Silvertip Creek and in Summit Lake, most likely due to winds overloading these various weak layers. In short, buried 1-2 feet deep are facets sitting on a crust at the mid-elevations and buried surface hoar at the higher elevations. Whumpfing has been widely reported in the mid elevation band region-wide. If headed out for a long day in the mountains, remember these layers are there and no red flags may be present before a slab releases.
Solar warming/effects: Sunshine today along with light winds may allow for enough warming to initiate small wet loose avalanches on steep Southerly aspects. Warming may also cause slabs to be more reactive; something to keep in mind as we choose our late afternoon terrain.
A wide angle view of Sunburst, Magnum, Cornbiscuit and Lipps – it may be March, but a generally thin snow cover remains
Weak layers in the snowpack at the mid-elevations on the South end of Seattle Ridge
Overcast skies and snow flurries were over the region yesterday, with a trace of snow accumulating. Temperatures were in the upper 20’sF at 1,000′ and around 20F along ridgelines. Ridgetop winds were light and variable during the day before shifting Northwesterly overnight and picking up to the 5-10mph range. Temperatures also cooled to the teens overnight with colder air moving in.
Today, Sunday, we are expecting mostly sunny skies with light Northwest ridgetop winds (5-10mph). Temperatures are expected to rise to 30F at 1,000′ and to the mid-20’sF along ridgelines.
Tomorrow, Monday, clouds move back in with another chance for snow flurries (little accumulation). The big news is later this week, a larger low-pressure system is forecast to move into the Gulf of Alaska. This could bring a much better chance for snowfall to the Turnagain area and Western Prince William Sound. Stay tuned!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||28||trace||0||68|
|Summit Lake (1400′)||18||0||0||28|
|Alyeska Mid (1700′)||23||trace||0.02||60|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||20||NW||7||20|
|04/10/21||Turnagain||Observation: north sides||lance breeding|
|04/09/21||Turnagain||Observation: Girdwood to Turnagain Road Observations||W Wagner Forecaster|
|04/05/21||Turnagain||Avalanche: Resort bowl Seattle creek head wall||Clint Kyffin|
|04/04/21||Turnagain||Observation: Center Ridge||Andy Moderow|
|04/03/21||Turnagain||Observation: Repeat Offender – Seattle Ridge||Troy Tempel|
|04/02/21||Turnagain||Observation: Seattle Ridge||Wagner / Schauer Forecaster|
|04/01/21||Turnagain||Observation: Pete’s||Schauer/ Cullen Forecaster|
|03/31/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|03/30/21||Turnagain||Observation: Eddies||Johnston-Bloom / Kinney Forecaster|
|03/30/21||Turnagain||Observation: Sunburst North||lance breeding|
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.