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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, January 19th 2017
Created: Jan 19th 6:13 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.
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.
 Show the Complete North American Avalanche Danger Scale
LifeMed Alaska
Special Announcement

Placer area and 20 Mile are now OPEN to snowmachining. Please reference the bottom of this page for the latest snowmachine area openings on the Chugach NF. 

Join CNFAIC for our final Fireside Chat TONIGHT, Jan 19th! Aleph Johnston-Bloom will discuss how the current Turnagain area snowpack has developed over the winter, understanding the different avalanche problems described in the advisory and how to use them in decision-making. - Details HERE.

CNFAIC will be hosting a FREE avalanche rescue workshop in Turnagain Pass on Saturday, Jan 21st, at the motorized parking lot, 11-12:30am. This is a great opportunity to practice companion rescue with your beacon, shovel and probe and your partners and get a little feedback. This workshop is open to everyone and anyone, novices and experts, that recreate in avalanche terrain – snowmachiners, skiers, kicker-builders, etc!! More details HERE.


The Bottom Line

There is a MODERATE avalanche danger in the Alpine where triggering a fresh wind slab on leeward terrain is possible and in protected steep areas loose snow avalanches could be fast moving and run further than expected.  At Treeline and below the avalanche danger is LOW where triggering an avalanche is unlikely. 

***Placer and 20 Mile opened yesterday and there is limited information about the snowpack in these areas. Approach terrain with a cautious mindset and be on the lookout for Red Flags like recent avalanches, shooting cracks and collapsing. Practice safe travel protocols, always carry rescue gear and please let us know what you see out there!!!

***In the Girdwood Valley where 2.5'-3’ of snow fell this weekend, twice as much as Turnagain Pass, heighten avalanche conditions exist. Triggering a persistent slab 3+ feet thick or a larger is possible in Girdwood and should warrant extra caution!!!


Primary Concern

Yesterday Moderate Northwest ridgetop winds were seen blowing snow throughout our region loading many South and East aspects. Plenty of snow was available for transport and fresh wind slabs 1-2’ deep could be tender today. Steep, unsupported, leeward slopes in the alpine are the most suspect and a slab could break above you. Be on the lookout for drifted snow that has a pillow shaped appearance and don’t be surprised if slopes are loaded further down hill than expected. Evaluate the snow as you travel by testing small slopes and avoid high consequence terrain where the snow feels stiff, supportable or hollow sounding. Shooting cracks will be obvious clue that the snow is unstable. 

In Girdwood wind slabs may be thicker and could step down to an older weaker layer below. More caution is advised in this area.

Blowing snow along ridgetops was observed throughout the region yesterday, including the Placer Valley as seen below. Photo by Conrad Chapman. 

 


Secondary Concern

Today in areas protected from the wind triggering a loose snow avalanche will be possible on steeper slopes. Fast moving “sluff” could entrain snow, run further than expected and easily knock you off your feet. Manage this problem by letting the snow move past you and choose terrain that doesn’t have high consequences if you fall. Although it is unlikely to bury a person, keep in mind that larger terrain will have more volume. Cold temperatures could increase this problem throughout the week as the surface snow becomes even less cohesive. 


Additional Concern

A variety of weak layers exist within the snowpack and vary across our region. Following the most recent snowstorm (1/13-1/16) most of the avalanche activity has been observed in the Girdwood Valley. This makes sense since this storm favored this area and left 2-3’ of snow. A handful of small, but deep (to the ground) avalanches were spotted in the alpine yesterday on Southern aspects of Penguin Ridge, Raggedtop, and Magpie. It is unconfirmed if these all happened as a result of moderate NW ridgetop winds that started yesterday morning or if these happened near the end of the storm on Monday (1/16.) Either way triggering even a smaller persistent slab could bury a person or take you for a very unfavorable ride over rocks. If you see recent avalanche activity, experience shooting cracks, or “whumpfing” these are obvious clues that you should avoid steep slopes.

If traveling in the Placer and 20 mile zone, where we have little information about the snowpack, use caution if venturing into steep untested slopes. An observation yesterday confirmed significant wind transport along ridges in this area and there is also a possiblity of triggering a slab on an older deeper layer of the snowpack. It always advised to ride slopes one at a time, have a escape route planned, watch your riding partners and avoid terrain traps like steep gullies. Ease into terrain and let us know if you see an signs of instability today. 


Recent avalanche activity in the Crow Pass area on South aspects of Magpie. More photos of recent avalanche activity in Girdwood Valley can be found HERE.

 

 


Mountain Weather

Yesterday skies were clear and temperatures hovered between 0F to -5F. Northwest winds bumped into the 20-35mph range along ridge tops and remained moderate overnight. No new precipitation was recorded. 

Today looks similar with temps around 0F and another day of clear skies. NW winds will continue to blow 10-20mph, but should decrease by late afternoon to 5-15mph range.

Tomorrow expect a slight increase in temperatures (15F) and a possibility of scattered snow showers. There is talk of the cold arctic over Southcentral, AK breaking up as low pressure tracks into the Gulf late this weekend.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') -2  42 
Summit Lake (1400') -9  14 
Alyeska Mid (1700') -2  40 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') -4  WNW  10  32 
Seattle Ridge(2400') -1  14  53 

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: Dec 08, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedRain and snow have fallen in Turnagain Pass this week, but not enough to open for snowmachining. Continue to check back to this site for updates.
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.
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