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Avalanche Advisory

Turnagain Area Avalanche Advisory
Thursday, January 10th 2019 5:25 am by Heather Thamm
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

A generally LOW avalanche danger exists across all elevations bands for the Turnagain area. Triggering a slab avalanche is unlikely but not impossible. Glide cracks may release into avalanches. Limiting/avoiding exposure under them is prudent. Give cornices a wide berth and watch your sluff.

SUMMIT LAKE / JOHNSON PASS / LYNX DRAINAGE: Keep in mind buried weak layers exist in the middle and base of the snowpack. More potential for triggering a large slab avalanche exists in this zone. Choose terrain wisely and please read the Additional Concerns below. 


 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.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Special Announcement

Check out our calendar for upcoming avalanche classes and events in January! Lots of opportunities with all the avalanche education providers in the area.


Avalanche Problem 1

Despite our generally stable conditions, it is still important to look for signs of instability as the mountains can surprise us at times. Periods of localized ridgetop winds over the last two days have transported some surface snow. Finding an isolated wind slab is not out of the question. The last avalanche triggered was over a week ago and cold temperatures have been helping the snowpack adjust. Observations and snowpack tests have been pointing towards a stabilizing snowpack.

Low danger does not mean no danger. Practice good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are key ways to minimize risk. Ease into steep terrain and factor in the consequences should you encounter one of the following:

  • Glide avalanche:  
    • Identify glide cracks and avoid spending any time under these features. Glide cracks are opening and have avalanched within the last week. Glides are completely unpredictable and not human triggered.
  • An outlier slab avalanche: 
    • Triggering a slab avalanche would most likely occur on an exposed 'unsupported slope' that sits above a cliff or steep rocky terrain. A wind slab or a pocket of buried surface hoar 1-3' below the surface may be lurking in an isolated area.
  • Cornice fall: 
    • Remember cornices often break farther back from ridges than expected. Give them a wide berth.
  • Loose Snow Sluffs:
    • Be aware of fast moving surface snow in steep terrain. Sluffs are slowly becoming larger as the cold weather weakens surface layers.

 Glide cracks and wind textured snow on the SW face of Tincan Proper. Photo taken yesterday 1/9/18 compliments of Allen D. and Eric R. Glide cracks are present in a lot of popular terrain and can be hard to see until you're suddenly near one.


Additional Concern

Persistent Slabs

South of Turnagain - Lynx Creek/Johnson Pass/Summit Lake zone:  A poor snowpack structure exists in these areas. The buried surface hoar that we have been talking about over the past week has been found as well as facet/crust combinations in the bottom of the snowpack. The last avalanche cycle was over a week ago during the New Year's storm, and overloaded a variety of these weak layers in Summit Lake. Cold weather this weak has been helping stability around the area, but steep slopes without debris below remain suspect. If you're headed this way, the snowpack becomes more complex - evaluate terrain exposure and the snowpack as you travel.


Mountain Weather

Yesterday: Skies were partly cloudy becoming overcast in the afternoon with a period of light snow showers. A trace of snow was observed. Temperatures were in the teens F in the upper elevations and dropped into the single digits overnight. Valley bottom temps increased from single digits F to teens throughout the day. Ridgetop winds were light 5-15 mph from the NW with a few hours in the 10-20mph range.  

Today: Expect clear skies and single digit temperatures in the upper elevations with slightly warmer valley temps. Temperatures in the alpine are expected to drop into the negative digits by this evening. Ridgetop winds should remain light from the NW winds. No precipitation is expected.

Tomorrow: Clear skies and single digit temperatures will continue through tomorrow before a weather pattern shift on Friday night. A series of fronts associated with a low-pressure system moves into the Gulf of Alaska bringing warm, windy and wet conditions by Sunday.  This is our next chance for snow with rain expected near coastal areas.

*Seattle Ridge weather station was heavily rimed and the anemometer (wind sensor) was destroyed. We are currently working to replace it. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 15  0 54 
Summit Lake (1400')  6 20 
Alyeska Mid (1700') 10  trace  42 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') WNW  23 
Seattle Ridge(2400') 13  *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: Jan 13, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Open
Placer River: Open
Skookum Drainage: Open
Turnagain Pass: Open
Twentymile: ClosedClosed. Forest Service is monitoring conditions.
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Primrose Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

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
© 2019 Chugach National Forest Avalanche Information Center. All rights reserved.
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