We received multiple reports of skier and snowboarder-triggered storm and wind slab avalanches yesterday. Most of these were not big enough to bury a person, but they did grab our attention. Nobody was caught or carried in any of these avalanches.
|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|
In the past two days, we have gotten reports of several human-triggered avalanches failing on the interface between the most recent storm snow and a weak layer of buried surface hoar and near-surface facets. Most, if not all, of these avalanches have occurred on slopes that had seen recent wind loading. Similar activity will be the main concern for today. We are not expecting to see any extraordinary winds during the day, but it will not take much to move the low-density snow on the surface into sensitive slabs. If your travel plans for the day involve any kind of steep terrain, it will be important to pay attention to changing conditions at the snow surface. Even a subtle increase in surface hardness could be enough to make a dangerous combination of a slab on top of very weak snow. Be on the lookout for red flags indicating increasing instability, such as shooting cracks and fresh avalanche activity. The most likely places to find unstable snow today will be near ridgelines, below convexities, or on cross-loaded slopes. With winds forecast out of the west, we might see slabs forming in unusual places today.
Sluffs: The low-density snow at the surface has been producing sluffs in steep terrain. These avalanches are not big enough to bury a person, but they could have serious consequences if they carry you into terrain traps like cliffs, trees, or rocks. If you plan on heading into steep terrain, be aware of these dry loose avalanches, and of exposure to consequential terrain below.
Cornices: We have recently seen large cornices peeling away from ridgelines, opening up large cracks (there are some good photos here). Be sure to give them plenty of space, and minimize the amount of time you spend below them.
Cornices are starting to peel away from ridgelines, opening up large cracks. These cracks can sometimes be difficult to identify when they get bridged with blowing snow. Bertha Creek Headwall. Photo: Tony Naciuk. 01.30.2021
We have been seeing more glide cracks open up recently. Glide avalanches are large and destructive, and their timing is impossible to predict. Avoid traveling on or below slopes with glide cracks, and let us know if you see any new ones open up.
Yesterday: Winds were calm to light, blowing 0-10 mph at ridgetops. High temperatures were in the upper teens to low 20’s F, with lows in the single digits to low teens F overnight. We saw plenty of sunshine and no precipitation under clear skies.
Today: Similar weather continues today, as an upper-level ridge of high pressure stays in the area. We expect to see temperatures reach the low to mid teens F, with light winds 5-10 mph out of the northwest. We should see another sunny day, with no precipitation expected.
Tomorrow: Lows will drop down into the single digits tonight, and stay around 10 F tomorrow. Light westerly winds will continue, with another day of clear skies expected. No precipitation is expected tomorrow.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||N/A*||N/A||N/A||N/A|
|Summit Lake (1400′)||N/A||N/A||N/A||N/A|
|Alyeska Mid (1700′)||16||0||0||109|
*Snotel sites are not reporting as of 6:45 a.m.
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||13||NE||3||8|
|05/18/21||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|04/30/21||Turnagain||Observation: Sunburst||W Wagner Forecaster|
|04/27/21||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|04/26/21||Turnagain||Observation: Magnum||Creighton/ Hoople|
|04/25/21||Turnagain||Observation: Sunburst||Nick D'Alessio|
|04/24/21||Turnagain||Observation: Airplane obs||Johnston-Bloom / DiJulia /Hilliard Forecaster|
|04/24/21||Turnagain||Observation: Corn biscuit||Heather Johnson|
|04/23/21||Turnagain||Avalanche: Lynx Ck Drainage||W Wagner Forecaster|
|04/23/21||Turnagain||Avalanche: Sunburst||Eeva Latosuo|
|04/23/21||Turnagain||Observation: Center Ridge Turnagain pass||Joe Kurtak|
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.