Avalanche Advisory

Turnagain Area Avalanche Advisory
Wednesday, April 6th 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 potential for mid-elevation glide avalanches is keeping the avalanche danger at CONSIDERABLE today. These are most pronounced at 3,000' and below. Many popular slopes are harboring dark brown glide cracks that have potential to release day or night.  Cautious route finding and careful terrain evaluation is essential to avoid being under the run out of glide cracks!

The avalanche danger is LOW in the alpine where a stout and supportable surface crust sits under 2-4” of wet snow from yesterday. 

*As glide avalanches continue to release, summer use trails with avalanche terrain above should be avoided. The Byron Glacier trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood, remains CLOSED.

 Show the Complete North American Avalanche Danger Scale
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
0 NO RATING Below Treeline / Below 1,000'
Special Announcement

FREE rescue clinics and general avalanche information for those headed to Arctic Man this week.  Click HERE for more information.  The snowpack has been reported to be very unstable in the Hoodoos with many human triggered avalanches over the weekend. Please be on your guard and don't forget your beacon, shovel and probe.


Avalanche Problem 1

Glide avalanches continue to steal the limelight and for good reason as it only takes a short drive through Turnagain Pass to witness first-hand the quantity of glide avalanches and sheer destruction that these can bring.  It is important to stay well away from existing cracks and limit your exposure time to glide avalanche run out zones.  We’ve been saying it for a while but to get caught up in a glide avalanche will undoubtedly prove fatal.

A very large glide crack has been slowly opening and creeping toward the common snowmachine up-track on Seattle ridge.  If venturing toward the back bowls today, travel fast in order to limit your time spent exposed to this growing glide crack.

Avalanche Problem 2

Wet loose avalanches:  2-4” inches of wet snow yesterday fell on a supportable crust above about 2,000’.  We can expect up to another 2-4” today.  Stubborn, shallow wet-loose avalanches may be possible in very steep alpine terrain but these shouldn’t prove much of an issue for skiers or snowmachiners today. 

Keep in mind that LOW danger does not mean NO danger.  Aside from glide avalanches, we haven’t seen much wet slab activity yet but it is getting to be that time of year where wet slabs become a concern with shallow overnight freezes and warm daytime temperatures.  

Cornices:  We are still waiting for the Alpine to warm up enough to start seeing a natural cornice fall cycle.  We do know that cornices are close enough to failure that skiers or snowmachiners can influence a failure by travelling on a corniced ridge and the potential for a human-trigger is a very real concern.  Remember these have a tendency to break much further back than one might expect.

Wind slabs:  Winds picked up enough overnight that high in the alpine (where dry snow exists) shallow wind slabs likely exist in leeward terrain.  These are not likely to be deep or large, but could prove tricky in extreme terrain.

Mountain Weather

Yesterday was mostly cloudy with light winds from the east.  Temperatures averaged 29 degrees during the day on Sunburst (3,880’) with 2-4” of new snow falling above about 2,000’ and light rain below.  Overnight, it looks like there was another shallow freeze between 2,000’ - 4,000’.

The forecast today calls for partly to mostly cloudy skies again with rain/ snow showers throughout the day.  We may see 2-4” of new snow above about 2,000’ and light rain below.  Temperatures will be in the low 40’s at 1,000’ and low 30’s to high 20’s around ridgetop locations.  Winds will be primarily from the East in the 15 – 35mph range. 

Tomorrow and into Friday may bring us a brief break from this showery regime before returning to unsettled weather over the weekend.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 37  .1  117 
Summit Lake (1400') 38   0 36 
Alyeska Mid (1700') 35   trace/ rain .14  103 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 28  E 11  38 
Seattle Ridge(2400')  29  SE 15  28 

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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