Avalanche Advisory

Turnagain Area Avalanche Advisory
Tuesday, February 9th 2016 7:00 am by Graham Predeger
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger is MODERATE today above treeline where fresh wind slabs 1-2’ thick will be possible to trigger on freshly wind-loaded slopes.  Cornices are also of serious concern in the alpine as they are large and tender right now.  In the mid-elevation band, glide cracks are numerous and avalanching full depth, generally on their own schedule. 

Note: The Girdwood Valley saw a lot more precipitation than Turnagain pass yesterday (see weather table below).  If headed into the backcountry around Girdwood expect fresh storm snow instabilities in addition to wind slabs and cornices.

 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.
0 NO RATING Below Treeline / Below 1,000'
Special Announcement

The Chugach National Forest Avalanche Information Center and Friends of the Chugach Avalanche Information Center are pleased to announce the launch of an observations program partnership with Hatcher Pass Avalanche Center.

By clicking the “Observations” link on both and, users can now browse and submit Hatcher Pass observations. Data is mirrored on both sites giving Southcentral Alaska backcountry enthusiasts the ability to quickly browse recent snowpack and avalanche observations throughout the region. Please submit your own observations and spread the word to others.  Huge thanks to all those folks who have already submitted observations!

Save the dates! Hatcher Pass Avalanche Center and Friends of the CNFAIC are also joining forces to support FREE avalanche education at Hatcher Pass and in Palmer. There will be a FREE companion rescue workshop on Saturday, February 13th, 10:30am-12:30pm, Hatcher Pass Gold Mint Lot and a FREE avalanche awareness class Wednesday, February 17th, 6:30-8pm, Palmer High School Library. Click HERE for more info!

Avalanche Problem 1

Wind Slabs

Almost Certain
Very Likely


Very Large


Today is expected to be a bit of an ‘in-between-storms’ type of day as we usher out yesterday’s windy and wet (Girdwood) weather and gear up for more active weather and a warm-up before the weekend.  Winds were steady in the 25-40 mph range for much of yesterday with gusts in the 60’s mph on Sunburst.  With substantial snow available for transport in the alpine, wind slabs 1-2’ deep will be possible to trigger.  For skiers, quick hand shears or probing with your pole will be a good way to identify areas where strong (wind slab) over weak snow exists in the alpine.  For snowmachiners, look for small, no-consequence test slopes to cut with your machine.  Any shooting cracks or hollow-feeling snow is indicative of a reactive wind slab.  Generally, these will be found on leeward terrain, with a southerly or westerly tilt today.


Cornices are notorious for catching people off guard and can break much further back than you might expect.  Travel well away from the edge of a corniced ridge in order to give yourself that extra wide berth.  Warming temperatures, direct sun and generally, any changing weather will continue to push these closer to failing naturally.

Avalanche Problem 2

Glide Avalanches

Almost Certain
Very Likely


Very Large


We’ve still got literally hundreds of glide cracks littering the mid-elevations in and around Turnagain Pass.  Many of these may not release at all, but we continue to see large and destructive glide cracks avalanching in or adjacent to popular ski terrain.  Completely unpredictable, it’s best to minimize your exposure to this volatile avalanche problem by avoiding time spent below glide cracks.  

Recent glide release on Pete's South.  This avalanched sometime Saturday night or Sunday morning.  The photo's really don't do it justice, this is a large and destructive avalanche!

Additional Concern

Persistent Slabs

Observations yesterday from the Lynx Creek drainage (South of Turnagain Pass) found a layer of buried surface hoar (BSH).  Likely deposited during the high-pressure weekend of Jan.30/31, it’s now buried by a 2-3’ slab.  Our one data point yesterday showed the BSH to be unreactive.  That is the good news, but given the nature of persistent weak layers, I’m not comfortable going all-in quite yet.  This is a similar structure to what Wendy and I found on Jan.31st, one drainage to the East… Buried surface hoar was unreactive in our pit, a mere quarter mile away from a very large and connected snowmachine-triggered avalanche from the previous day.  Bottom line: Don’t trust a hoar.


Mountain Weather

Low clouds and incessant rain pounded the Girdwood and Portage Valleys most of the day while the lucky few continued their march toward Turnagain Pass and partly sunny skies!  Temperatures were hovering around 32 degrees at the Pass with cloud cover in and out throughout the day with only about an inch of new snow.  Ridetop winds were steady in the 25-40mph range, gusting in the 60’s.  The Girdwood Valley received the lion share of precipitation yesterday measuring .85” of water and about 9” of snow at Alyeska mid-mountain (1700’).

Today we can expect partly cloudy skies with an overall clearing trend toward tonight.  We may see a couple inches of new snow and light rain below about 1200’.  Winds will be moderate from the East in the 15-25mph range.

This next round of storms will begin impacting our area from the South tomorrow/ tomorrow night.  Unfortunately temps look to be unseasonably warm with this next shot of active weather.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880')  30  .1 109 
Summit Lake (1400') 31.5  .1  31 
Alyeska Mid (1700')  31.5  .85 95 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  24  ENE 17  65 
Seattle Ridge(2400') 26  n/a  n/a  n/a 

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: Oct 05, 2019 )

Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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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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