Avalanche Advisory

Turnagain Area Avalanche Advisory
Tuesday, January 16th 2018 4:21 am by Aleph Johnston-Bloom
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger will rise to HIGH today at all elevations above 1000' due to a storm impacting the region bringing rain, snow and strong winds. Natural and human triggered slabs 2-5+ feet deep will be likely today in avalanche terrain and may step down to older weak layers. Rain may trigger large wet loose avalanches. Travel is not recommended on slopes steeper than 30 degrees and in all runout zones. 

The avalanche danger is CONSIDERABLE below 1000’ where natural avalanches from above are possible in steep channeled terrain. 

 Show the Complete North American Avalanche Danger Scale
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Treeline / 1,000'-2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
Avalanche Problem 1

Deep Persistent Slabs

Almost Certain
Very Likely


Very Large


Additional load, either from rain or snow combined with high winds, will be stressing the persistent weak layers of snow we know exist in the snowpack. We have two concerning layers of buried surface hoar and the last two days we have seen remote triggered avalanches. We have also seen avalanches stepping down and failing in weak snow near the ground. If somehow the weather doesn't turn you away from the mountains, it is important to realize that travel in avalanche terrain is not recommended. Stay out of runout zones. Up to an inch of rain is forecasted to fall to 3000', maybe higher. Rain to can add weight and stress the snowpack quickly. Avalanches today could be very deep and dangerous. Above 3000' we could receive over a foot of heavy wet snow. Cornices may also release naturally and trigger slopes below.

Yesterday morning observers noticed that another portion of the Seattle Ridge avalanche path, that was observed releasing on Sunday, had also slid. The trigger is unknown. Sunday's slide is believed to have been a remotely triggered by snowmachiners on the ridge above. This is one of the avalanches that stepped down to the ground. 

Skiers yesterday triggered a large avalanche on Eddies that connected down the ridgeline, while ski cutting a lower angle slope nearby. They reported seeing shooting cracks and then watched the slope release. The crown was 1-5' deep (average 3'), connected approximately 600' down the ridge and ran 700' down the slope. No one was caught or carried. The January 11th buried surface hoar is the suspected weak layer.

Eddies avalanche, 1.15.18. Photo: Susan Goodwin

On Sunday we recieved reports of a cornice triggered slab in Main Bowl. Here is a photo of the avalanche in motion. The cornice fall is believed to have been triggered by the snowboarders on the ridge. Photo: Eric Moore


Avalanche Problem 2

Wet Loose

Almost Certain
Very Likely


Very Large


As the rain falling today saturates the surface snow to 3000' and possibly higher expect loose wet avalanches. They are often preceded by roller balls as rain falling on dry snow can quickly break apart the bonds between snow grains. Surface snow can start failing in a point and fan out. Wet loose avalanches can gain mass as they move down hill and gather snow. They could be quite dangerous today and not something you want to mess with. These can also be triggered by skiers or riders in steep terrain. If water actually moves through the slab to the weak layers or crusts below we could get a wet slab avalanches later in day. 


Mountain Weather

Yesterday skies fluctuated between broken, overcast and completely obscured. There were rain and snow showers in the afternoon, with rain falling as high at 1700'. Temperatures rose into the 30Fs. Winds were light and easterly with few gusts into the 20s.

Today is forecasted to be overcast with up to inch of rain falling to around 3000', maybe higher. Rain could be heavy at times. Temperatures will be in the mid 30Fs at upper elevations and we could see as high 40F at 1000'. Winds will be easterly 25-35 mph gusting into the 50s. Rain fall looks to intensify tonight but rain/snow line looks to be lower, around 2400'. Temperatures overnight will be in the mid to high 30Fs and winds will be easterly, gusting into the 60s. 

Tomorrow will see a precipitation tapering off and temperatures dropping into the teens overnight. Clear, sunny weather looks to be on tap for the remainder of the week into the weekend. 

PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 32   .3 59 
Summit Lake (1400') 28 1 .2  16 
Alyeska Mid (1700')  34 .3  46


RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  27  ENE 10  25 
Seattle Ridge(2400') 30  SE  23 

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).

Winter snowmachine use open/closed status and riding conditions updates

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Mar 15, 2018 )

Glacier District
Johnson Pass: Open
Placer River: OpenPlease avoid private property and AKRR job site at Luebner Lake. Cross railroad tracks if needed, do not ride down tracks, it is illegal.
Skookum Drainage: OpenCross railroad tracks if needed, do not ride down tracks, it is illegal. FYI, Skookum drainage closes to Snowmachines on 4/1 as per the Chugach NF plan.
Turnagain Pass: Open
Twentymile: OpenCross railroad tracks at designated spot as you leave the parking area.
Seward District
Carter Lake: Open
Lost Lake Trail: Open
Primrose Trail: Open
Resurrection Pass Trail: OpenResurrection Pass trail is open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.

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