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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, April 12th 2016
Created: Apr 12th 5:53 am
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
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'
 Show the Complete North American Avalanche Danger Scale
Special Announcement
  • This will the final week of daily avalanche advisories. Between Monday, April 18th and Saturday, April 30th we will be issuing advisories on weekends and intermittently during the week.

  • The Chugach National Forest has closed some riding areas to motorized use due to snow melting out. Please see the table at the bottom of this page for a complete list. Snug Harbor, Summit Lake and Turnagain Pass (N. of Granite creek) will remain open. 

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, human triggered wet loose avalanches are possible in steep terrain that harbor wet and saturated snow.

In the Alpine the avalanche danger is MODERATE. Human triggered wind slabs are possible on leeward slopes and cornices remain a hazard along ridgelines. 

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

If you are headed to the Summit Lake area don't forget to check Summit Lake Summary 


Primary Concern

Glide avalanches remain our primary concern as they continue to release in areas we recreate. The most concerning zone is Seattle Ridge and the popular motorized up-track. This well traveled slope is hanging in the balance (pictured below). Although much of the snowpack has already avalanched along Seattle Ridge, there is still more to come... Due to the dangerous and destructive power of even a small glide avalanche, we are recommending that people do not travel in avalanche terrain (including runout zones) on the motorized side of Turnagain Pass (West Side). Glide avalanche hazard also exists on the non-motorized slide of Turnagain Pass. Travel underneath existing glide cracks is not recommended. In addition, be on the lookout for new glide cracks forming. 

New glide avalanche activity (from the past 24-hours) includes Max's South face, and two on Easterly facing slopes in the Summit Lake area. 

Photo: Max's Southerly face - this glide released mid-slope and you can see a crack to the looker's left that is prime to release:

 

Photo: Summit Lake fresh glide avalanche. There is little snow on these slopes but they still clearly pose a threat!

 

Seattle Ridge Glide Activity:
Although visibility was poor yesterday it looks as though no new glide avalanches occurred. We should be able to see these as they create such brown streaks and dirty debris piles. However, there may have been new wet snow avalanches considering it was difficult to see white(ish) debris.

Photo: Repeat Offender slide path with older glide avalanches running over the lower part of the up-track and cracks threatening rest of the up-track:

 

Seattle Ridge glide older glide activity seen across from the motorized lot:



Secondary Concern

As temperatures rise today watch for any superficial re-freeze of the snow surface to soften; if the sun pokes through this will speed up the process dramatically. How much re-freeze occurred last night is tough to tell as the cloud cover was in and out (clear skies overnight can re-freeze the surface even in temperatures are as warm as 40F....due to longwave radiation loss). If you find yourself on a steep slope with saturated wet snow then triggering a wet loose avalanche, or push-a-lanche, in steep terrain will be possible.


Additional Concern

At the uppermost elevations, where dry snow exists, watch for lingering wind slabs on steep leeward slopes. These areas are in the 3,500' range and higher. Also, cornices could start falling any day now with these warm temperatures and limiting time under them as well as giving them a wide berth is recommended.


Mountain Weather

Partly cloudy to obscured skies filled the region yesterday. Light precipitation fell along Turnagain Pass adding up to 2" of new snow above 2,500' and .2" of rain below. Ridgetop winds were averaging in the 10-15mph range with gusts to 40mph from the East at the Sunburst weather station.

Today, we should see clouds move in with a chance for breaks in cloud cover here and there through the day. No precipitation is expected and temperatures are slated to be warm.....up to 45F at 1,000' and 35F on the ridgetops. Ridgetop winds are expected to be ~10mph from a generally Easterly direction.

Looking forward to Wednesday and later this week, we remain in an unsettled weather pattern as a series of low-pressure systems spin to our South in the Gulf shooting moisture our way.

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 34  0.2  115 
Summit Lake (1400') 36  32 
Alyeska Mid (1700') 36  101 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 24  NE  15  46 
Seattle Ridge(2400') 30  SE  12  30 

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 25, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: Open
Skookum Drainage: OpenSkookum drainage closes to motorized use on April 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
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.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
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