CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, January 14th 2016
Created: Jan 14th 6:03 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.
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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
 Show the Complete North American Avalanche Danger Scale
The John Byrne Family
Special Announcement

Filing for the PFD this week? Remember, The Friends of the CNFAIC is part of PICK.CLICK.GIVE. Your donations are greatly appreciated and an integral part to making the CNFAIC possible and sustainable.


The Bottom Line

Today a MODERATE avalanche danger exists at and above Treeline where cornices should be avoided and lingering wind slabs are possible in steep terrain.  At Treeline, glide crack movement has been active including several that have avalanched to the ground over the last few days. These unpredictable hazards can release unexpectedly and should be avoided. Today’s avalanche concerns require you to be aware of what is above and below you and avoid specific high consequence hazards.

Below Treeline the danger is LOW where triggering an avalanche is unlikely.

Yesterday buried surface hoar was found in Lynx creek where a shallower snowpack exists. Similar to Summit Lake, more caution and careful snowpack evaluation is essential on the Southern side of our forecast zone. See the most recent Summit Lake Summary for snowpack observations


Primary Concern

Yesterday’s poor visibility made it challenging to see this unpredictable hazard. We received a report of a glide release on Seattle Ridge yesterday, but the exact location is unknown at this point. Glide cracks are appearing all over Turnagain Pass between 1000’ to 2500’ and are showing up in popular areas. Monitoring their movement is helpful, but there is no discernable pattern to predict a failure as they tend to fail naturally and on their own schedule. Warm temperatures can trigger them and so can cooling temperatures. Cracks can form and release in seconds or days later or sometimes a glide crack won’t release at all, and benignly just fill back in with snow.

Glide cracks are best to be given a wide berth.  Limit your exposure time spent underneath and if skiing or riding in terrain with glide cracks, try and map them out before your travels so as not to end up directly on top of or inside one.  Remember, when these do fail, they tend to be destructive, failing to the ground bringing the entirety of the snowpack with them.  

Along Seattle Ridge glide cracks are becoming more abundant in specific locations. Avoidance of these unpredictable harzards is key. Thanks for the photo and observation Travis!

 


Secondary Concern

Cornices have grown considerably during the past few weeks. Not only do they have the potential to fall naturally, but also to be triggered by the weight of a person or snowmachine. They can also trigger an avalanche on the slope below when they fall. Travel under or on them should be avoided. Today's weather forecast should make travel into the Alpine easier with good visiblity, thus don't forget cornices have the tendency to break farther back from the ridge than expected.   


Additional Concern

As we move further away from our most recent storm event that ended on Jan.11 wind slabs are becoming a low likelihood concern. However triggering a lingering wind slab could have high consequences in places with cliffs, rocks, or trees below. Obvious signs like shooting cracks may not be present until its too late, as wind slabs are known for breaking above you, once you are well onto a slab. Ease into steep terrain and avoid terrain features with high consequences.

*Yesterday we received a report of buried surface hoar found in a snow pit in Lynx Creek.  This weak layer is more suspect in protected areas of the snowpack, but could be more widespread in this region. Similar to Summit Lake areas, Johnson Pass and Lynx Creek have a shallower snowpack where conservative terrain choices should be utilized. 


Mountain Weather

Yesterday light snow fell in Girdwood and Turnagain Pass leaving trees with over an inch of white stuff. Valley fog was also observed. Winds were clam from the East and temperatures remained just below freezing, <30F.

Today skies are expected to be mostly sunny becoming partly cloudy by mid afternoon. Patches of Valley fog could obscure visibility at lower elevations with a chance of light snow in the afternoon.  Temperatures will be in the mid 20F’s today. Expect light ridgetop winds from the East.

*Wind data from Sunburst Weather Station is from 2pm to 6am, due to a rimed anemometer that is now fixed.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880')  26 trace  84 
Summit Lake (1400') 28  trace   0 27 
Alyeska Mid (1700') 27  .17  63 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 25  *E  *3  *13 
Seattle Ridge(2400')  25 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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

Subscribe to the Turnagain Area Avalanche Advisory:

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
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
FCNFAIC