Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, March 5th 2018 7:00 am by Wendy Wagner
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger remains MODERATE above 1000’ on all aspects. Old wind slabs, up to a foot thick and sitting on weak snow, will be possible to trigger along ridgelines and in cross-loaded gullies. A larger slab avalanche (up to 2' or more thick) that breaks in weak layers deeper in the snowpack also remains possible above 1,000'. 

 Show the Complete North American Avalanche Danger Scale
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Special Announcement

Human triggered avalanches continue to be reported region-wide, one at Hatcher Pass and another in the Western Chugach (Hiland Road) occurred yesterday. Snow last week followed by strong wind increased the avalanche conditions, which may continue to linger in many areas of Southcentral, Alaska.

Avalanche Problem 1

Persistent Slabs

Almost Certain
Very Likely


Very Large


After a month with very little precipitation, weather models are showing potential for a snowy week ahead of us. This is good news for powder hungry folks, but we can't forget about our current state of the snowpack. As we have been discussing for some time, there are several weak layers in the pack that continue to show signs of reactivity. Hard wind slabs formed by last week's wind event are, in some cases, overlying these buried weak layers. A human triggered avalanche in the Summit Lake area was proof of this last week. Hence, finding and triggering a slab avalanche remains a concern. 

Persistent slabs:  Buried 1-2 feet deep are facets sitting on a crust at the mid-elevations and 1-3' deep is a buried surface hoar/facet combo at the higher elevations. The mid-elevation faceted layer seems to be the culprit for many reported 'whumpfs'/collapses lately and is the layer responsible for the Summit Lake avalanche. Although the heart of Turnagain Pass has these layers, they are more pronounced and developed on the Southern end of Turnagain Pass and in Summit Lake where the snowpack is shallower. Areas to the North, such as Crow Pass, could also be suspect along with those that have not seen much traffic this season. Until we receive a significant load (hopefully this week), triggering these layers are becoming more and more stubborn with time. Continuing to use safe travel protocol and assessing consequences if a slab does release will be key in choosing terrain. The snowpack we have now will likely let us get away with a lot - but probably not everything. 

Hard wind slab on faceted snow - Summit Lake/Tenderfoot avalanche that was human triggered last Tuesday (2/27).



Valley fog up to 2,500' limited visibility along some mid-elevations yesterday. 



Mountain Weather

Partly to mostly sunny skies were found above thick valley fog yesterday; fog lingered late in the day and up to 2,500'. Ridgetop winds were light (5-10mph) from the West and North. Temperatures stayed cool, in the teens along ridgetops, but warmed up in most valley bottoms to ~30F.

Today, Monday, we can expect mostly cloudy skies with a few snow flurries in the afternoon. Only a trace of accumulation is expected. Ridgetop winds will stay light from the Northwest (5-10mph). Temperatures plummeted to the single digits last night in valley bottoms and should bounce back to the 20'sF today. Along the ridgelines, temperatures will remain in the teens.

For tomorrow, Tuesday, cloudy skies and increasing Southeast winds will be over the area as a quick moving front moves through. Snowfall is expected Tuesday night. This flow direction is not ideal for Turnagain but we could see up to 6 inches. A series of storms will follow Tuesday night's event, the next system moving in Thursday/Friday. Stay tuned!


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 22  67 
Summit Lake (1400') 14  28 
Alyeska Mid (1700') 18  60 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 16  17 
Seattle Ridge(2400') 18  11 

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: May 06, 2019 )

Glacier District
Johnson Pass: ClosedClosed as of 4.3.19
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: ClosedClosed as of 5/6. Thanks for a great season all, see you next winter!
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
Seward District
Carter Lake: Closed
Lost Lake Trail: ClosedClosed as of 3.22.19 due to lack of snow
Primrose Trail: ClosedClosed as of 4.3.19 due to lack of snow
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: ClosedClose as of 5.1.2019
South Fork Snow River Corridor: ClosedClosed as of 3.20.19 due to lack of snow.
Summit Lake: Closed

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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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