Avalanche Advisory

Turnagain Area Avalanche Advisory
Saturday, April 16th 2016 5:34 am by Wendy Wagner
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

CONSIDERABLE avalanche danger remains on all slopes under 2,500' in elevation due to an active glide avalanche cycle. Destructive glide avalanches are occurring daily across the region. Avoid being under the runout of glide cracks. In addition to glide avalanches, natural wet loose avalanches are possible and human triggered likely in steep terrain that harbor wet and saturated snow.

In the Alpine the avalanche danger is generally LOW. Low doesn't mean no however and watching for lingering wind slabs, cornice falls (give these guys a WIDE BERTH!) and human triggered wet sluffs could be seen. 

***Travel is not recommended in avalanche terrain on the West (motorized side of Turnagain Pass).

*ATTENTION HIKERS: Summer use trails crossing under avalanche terrain should be avoided due to avalanche hazard from above. Byron trail in Portage Valley and Crow Pass are two examples of trails not recommended right now. 

 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
  • We are finished publishing weekly summaries for the Summit Lake zone. Please see the final Summit Lake Summary and springtime tips on this link. Reminder: as the season winds down, we will continue to publish all reports/observations sent in to us!

  • Tomorrow is the last day of daily avalanche advisories. Between Monday, April 18th and Saturday, April 30th we will be issuing advisories on weekends and Tuesday and Thursday during the week.

Avalanche Problem 1

Yesterday’s hampered visibility limited some information regarding new glide avalanche activity, however, we were able to get a look at Seattle Ridge and a few other areas along the Seward Highway. New avalanche activity seen yesterday:

New glide avalanches:
- Paths off of Pk 4940, across from the Granite Ck Campground (South facing, photo below)
- Penguin Ridge (South facing)
- Eddies (South facing)

*Note: no new glide releases were noted on Seattle Ridge

New wet avalanches:
- Wet loose avalanche above Bertha Creek Campground @ 3:30 yesterday
- Small wet loose slides and roller balls seen on Pete's South, Southerly aspect

This current wet snowpack, combined with today’s weather (light rain, cloudy and possible sun), has us prepared for another round of glide activity. Our message remains the same: to avoid being under glide cracks and respective runout zones. To be in the wrong place at the wrong time when a glide releases could likely be deadly. Considering the motorized up-track is threatened by cracks, we are recommending that people do not travel on the up-track or in runout areas along Seattle Ridge. Glide avalanche hazard also exists on the non-motorized side of Turnagain Pass in certain zones, most pronounced on Southerly aspects. 

Left photo: New glide releases on South facing Pk 4940.                Right photo: Glide releases on Seattle Ridge and a melting out snowpack.



Close up view of the Seattle Ridge snowmachine up-track. Several cracks threaten the route along with remnants of a natural wet loose avalanche that occurred Thursday (4/14)



Avalanche Problem 2

Yesterday temperatures rose to 32F at 2,500' and light rain and cloud cover since has likely kept the mid-elevation surface wet and unsupportable. It was no surprise to hear of a natural wet loose avalanche witnessed on a SE facing slope above the Bertha Ck Campground. These wet loose slides will be a concern again today with our warm temperatures. Any periods of sunshine will also be a factor and increase the chances for natural activity. Natural wet loose avalanches are possible on all aspects at elevations below 2,500' and human triggered wet loose sides are likely. In the Alpine, Human triggered wet sluffs are possible on slopes seeing warming by the sun.

*Remember wet loose avalanches can be hard to escape once initiated and particularly hazardous if they push you into a terrain trap.

Additional Concern

At elevations above 2,500' and in the Alpine the snowpack is generally stable. There are a few things to watch for if skies open enough for travel to the upper elevations:

- Lingering wind slabs that could be triggered in steep rocky terrain 

- Cornice falls (we have yet to see cornices start falling in the Alpine but this could happen any day with our warm temps)

- Wet sluffs on steep solar aspects

Mountain Weather

Yesterday's weather consisted of mostly cloudy skies and occasional light precipitation. Past 24-hour accumulations were up to 0.2" of rain up to 2,500' with 1-2" of wet snow above this. Areas on the South side of Turnagain Pass and Girdwood Valley saw only a trace. Ridgetop winds have been moderate, averaging 10-15mph with gusts to the 20's from the East. Temperatures rose to the low 40'sF at 1,000' yesterday (32F at 2,500') before cooling off to the mid 30's at 1,000' (upper 20's at 2,500').

For today, partly cloudy skies and intermittent rain showers are possible (trace of snow above 2,200') adding only 0.1" of water. It's possibly the sun could come out later in the day. Ridgetop winds will be ~10mph from the East while temperatures stay warm (rising to 45F at 1,000' and 32F at 2,500').

Sunday looks to be a short break between low-pressure systems that are churing in the Gulf. We could see sunshine along with high clouds and light winds. Another bout of moist Southerly flow looks to move in on Monday.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 36  rain  0.2  111 
Summit Lake (1400') 37  28 
Alyeska Mid (1700') 37  0.03  96 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 28   NE 12  28 
Seattle Ridge(2400') 30    SE  12  24 

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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