Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, January 1st 2018 5:30 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 is HIGH today at all elevations above 1,000'. Another round of strong wind and heavy snowfall will continue to overload a weak snowpack. Natural avalanches are likely today and tonight. Human triggered avalanches are very likely. As the new snow piles up on a weak layer of buried surface hoar and facets, avalanches are becoming larger and more dangerous. Travel in avalanche terrain is NOT recommended. 

The avalanche danger is CONSIDERABLE below 1,000’ where debris from avalanches above may run.

 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.
Special Announcement

*All of us at the CNFAIC would like to wish everyone a Happy, and safe, New Year!! Thank you for your support!*

Dangerous avalanche conditions are expected in the Southern Kenai Mountains (such as, Seward and Lost Lake) due to heavy snowfall.

Join CNFAIC on Wednesday, January 3rd from 7pm - 8:30 pm at the Blue & Gold Boardshop for a discussion on Understanding Weak Layers and the Current Snowpack at Turnagain Pass. 

Avalanche Problem 1

Storm Slabs

Almost Certain
Very Likely


Very Large


Yesterday's NYE storm (New Year's Eve) greeted many snow enthusiasts with joy. Storm totals were 12-20" at the mid and upper elevations from Girdwood Valley to Turnagain Pass. On the South side of Turnagain Pass, such as Sunburst and Johnson Pass, only 3-4" of snow fell... Snowfall amounts were very different from one ridge to the other with this storm. The part of the puzzle that is not joyful however, is a layer of surface hoar underneath the new snow. This has created poor bonding between the new and old snow; proved yesterday by the plethora of human triggered avalanches. To make matters a bit worse, under the surface hoar are near surface facets (another weak layer) and then a hard layer of crust or wind packed snow that is acting as a bed surface. All these ingredients point to likely human triggered avalanches. 

There is another storm headed in today. An additional 5-10" of snow is expected with another 6-12" tonight above 1,000'; rain/snow line should be around 500-700’. This will increase the load on the weak layers as well as the slab thickness to over a foot and up to 3' in places. The storm is coming in warmer and windier, which will also contribute to the increasing avalanche danger. Even small(ish) slopes could become hazardous if the slab is 3 feet thick instead of 1 foot. Keep this in mind if you are headed to the backcounty this week. Also, keep in mind remote triggering is possible from the side or below a slope. Steering well clear of runout zones will be key.

Yesterday's avalanche activity:
Human triggered avalanches were widespread in the Tincan Trees yesterday. All avalanches were soft slabs or wind slabs around 1-2' thick and failing on the buried surface hoar mentioned above. Photo below and comment from a group that triggered a larger avalanche in the Tincan Trees (16" deep, 150 wide and running 200' ). Triggered remotely by 3rd skier on adjacent slope - no one caught.

"We were pretty surprised at how much energy and how far it ran through trees."   (Photo Ray Koleser)


Photos of skier triggered soft slabs in the Tincan Trees yesterday. Smaller terrain, smaller slab, smaller avalanches.  (Photos by Trip Kinney) 



Shooting cracks





A look at the new snow sitting on weak layers with a harder wind packed surface below. All known avalanche activity seen yesterday on Tincan was due to the buried surface hoar.


Avalanche Problem 2

Deep Persistent Slabs

Almost Certain
Very Likely


Very Large


In the alpine, above 3,000’, rapidly loading slopes may awaken a large and dangerous deep slab avalanche. At these elevations, a hard slab, 3-5+ feet thick, is sitting on top of weak sugary snow (basal facets) near the ground. As new snow increases the load over this snowpack structure during the current storms, there will be the potential for large natural avalanches. Between storms, human triggered deep slab avalanches will be possible. This is a high consequence avalanche problem that is impossible to outsmart and can take a long time to heal. Keep this in mind as breaks between storms may allow for travel to the Alpine. 

Mountain Weather

Yesterday was a classic storm day on Turnagain Pass. Very low visibility, gusts winds and snowfall. Roughly 12 - 20" of new snow has fallen in the upper elevations of Girdwood Valley and the Turnagain Pass area. 24-hour totals are below in the table. Lesser snow amounts were seen on the South end of Turnagain Pass and in the Summit Lake area. Ridgetop winds were Easterly averaging 25-45mph with gusts to 80mph. Temperatures were in the mid 20'sF at treeline and around 30F at 1,000'. 

Today, New Year's Day, into Tuesday we have another storm moving in. This one will be warmer, windier and possibly wetter. The rain/snow line looks to rise to around 500-1,000' before lowering with cooler temperatures tomorrow. Snowfall amounts look to be 5-10" (.8" water) of heavier snow today with another 6-12" (.9" water) tonight. Ridgetop winds will be Easterly in the 30-50mph range with stronger gusts. Temperatures continue to climb to the mid 30'sF at 1,000' and upper 20'sF on the ridgetops.

On Tuesday the storm begins to move out and cooler temperatures move in. A break in storms is looking to be Wednesday and Thursday before another low-pressure heads our way. 


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 32  0.6  40 
Summit Lake (1400') 30  0.2  12 
Alyeska Mid (1700') 29  10  0.75  39 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 20  NE  37  80 
Seattle Ridge(2400')  24     SE   20  51 

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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