The snow that fell yesterday was light and fluffy and the kind that will easily blow around and form tender wind slabs. Overall the winds weren’t strong but there was period of more sustained wind last night. The new snow fell on surface hoar, near surface facets and sun crusts and was not bonding well. This should make winds slabs easy to trigger but due to limited snow totals the slabs shouldn’t be that deep (6″-1′). Look for pillowed or drifted areas in leeward terrain and pay attention to shooting cracks.
In areas not affected by wind there is also potential for shallow storm slabs and loose snow avalanches due to the new snow not bonding well to old snow surfaces. When the sun comes out today look for point releases on steep solar aspects.
Storm snow easliy failing on buried surface hoar in a shovel tilt test yesterday.
Buried surface hoar over a micro sun crust @ 2200′ on Sunburst yesterday.
Weak snow (facets and depth hoar) in the lower layers of the snowpack lingers as an issue in our advisory area. It has been 8 days since the last human triggered avalanches on these layers. However, triggering a deep slab is still a possibility if you find the wrong spot and a concern due to the depth of slab overlying the weak snow. The likelihood for someone to find and trigger a large slab is decreasing as the snowpack adjusts, but the poor snowpack structure remains and the consequences are scary. Both near miss avalanche accidents last week were triggered in thinner areas of the snowpack, on slopes that already had tracks on them. The tricky part about this particular avalanche problem is that it is very difficult to assess. Obvious signs like whumpfing and shooting cracks are unlikely and stability tests may not be reactive. Just because a slope has tracks on it does not mean it is safe. Likely places to trigger a deep persistent slab will be near rocks or in thin zones where affecting the weak layer is more of a possibility. Likely triggers are large: snowmachines, groups of people or cornice falls. Identify and avoid terrain traps (like large gullies).
Snow pit @ 2200′ on Sunburst yesterday. Note the soft (weak, faceted snow) under the hard slab.
Last weekend cornice cracks were reported along the back bowls of Seattle Ridge. A few chunks have been triggered this week. Remember these unpredictable hazards can break farther back onto a ridge than expected and have the potential to trigger an avalanche on the slope below. Give cornices extra space and avoid being under them.
Yesterday skies were obscured and light, low density snow fell throughout the day. Temperatures were around 0 in the Alpine and teens/single digits in valley bottoms. Winds were mostly light and shifted from the West to the North. There was an uptick in winds that saw gusts up to 40 mph in the early evening. Light snow showers continued overnight.
The chance for snow showers decreases this morning with clearing skies. Today temperatures will remain cold 3-13F and winds will be light and Northerly. Tomorrow the pattern shifts as warm, moist air moves in with the first of a series of low pressure systems on track to affect the area. Stay tuned for details!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||5||6||.3||58|
|Summit Lake (1400')||0||1||.1||25|
|Alyeska Mid (1700')||6||6.5||.2||53|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400')||-1||NNE||5||21|
|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.