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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Tuesday, April 5th 2016
Created: Apr 5th 4:21 am
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'
 Show the Complete North American Avalanche Danger Scale
Special Announcement

If you are headed to Arctic Man please stop by the large CNFAIC trailer for information regarding FREE rescue clinics and general avalanche information. We will also have a beacon park set up so you can practice your skills anytime, day or night. Click HERE for more information. The snowpack has been reported to be very unstable in the Hoodoos with many human triggered avalanches over the weekend. Please be on your guard and don't forget your beacon, shovel and probe.

 


The Bottom Line

The avalanche danger is CONSIDERABLE in the Turnagain pass and surrounding areas due to large destructive glide avalanches. These are most pronounced at 3,000' and below. Many popular slopes have dark brown glide cracks that could release at anytime and travel under these is discouraged. Cautious route-finding and careful terrain evaluation are essential to avoid being under the runout of glide cracks.

In the Alpine, where a stout surface crust has formed and there is a generally stable snowpack, the avalanche danger is LOW.

*As glide avalanches continue to release summer use trails with avalanche terrain above should be avoided. Byron trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood, remains CLOSED.


Primary Concern

Yesterday the glide activity was decreased in comparison to what we saw over the weekend. However, there were still a few glide avalanches observed near Girdwood Valley. The unpredictability and the threat of these releasing in terrain while people are recreating is keeping them as the primary concern at Turnagain Pass and surrounding regions. It is important to stay away from existing cracks, think about avalanche runout zones and observe where new glide cracks are appearing. 

On all aspects at elevations below 3,000' the snowpack, as a whole, continues to ooze down the slopes and create cracks (despite having a hard crust on the surface). There is no way to predict when a crack is going to release into a large full-depth avalanche.

The Seattle Ridge uptrack is one of our biggest concerns because a large crack now puts this popular route in the line of fire. If you were to be in the wrong place at the wrong time you would not survive a glide avalanche. High marking or setting a skin track under a glide crack is not recommended! 

Looking across to Seattle Ridge from Taylor Creek drainage.

Seattle Ridge uptrack with glide crack hazard.

 


Secondary Concern

Other than the scary glide avalanche issue normal caution is advised in the backcountry. The snowpack is generally stable and there is a stout melt-freeze crust on the surface extending to at least 4000'. Yesterday this crust remained frozen throughout the day with minor softening below 2000'. For today, clouds may limit surface warming but there may also be windows of sunshine.  Watch out for 'slide for life' potential in steep terrain, as the surface crust is very slippery.

Remember Low danger does not mean NO danger. Follow safe travel protocol and be on the lookout for changing conditions.

Here are a few other avalanche problems to keep in mind:

Wet loose avalanches: If there is enough rain and/or warming to disintegrate the crust at low elevations, wet loose avalanches may be possible in very steep terrain. 

Wind Slabs: Yesterday shallow wind slabs were observed on leeward terrain along ridgelines in Alpine. There is not much snow available for transport but as we get a bit more precipitation these may become more pronounced. These shallows slabs are sitting on the slick crust and could surprise you in steep terrain.

Cornices: We are still waiting for the Alpine to warm up enough to start seeing natural cornice falls. These giant features are still holding on and looming. The potential to trigger one from the ridge is a very real concern. We received a report of a snowmachine triggered cornice incident near Whittier on Sunday. Remember these can break further back than expected. 

 


Mountain Weather

Yesterday was mostly cloudy with moderate easterly winds. Temperatures were in the mid 20Fs @ 3000' and the mid 30Fs to 40Fs @ 1000'. 
There were light rain/snow showers overnight and temperatures in the mid 20Fs to mid 30Fs. Winds were gusty from the east.

Today is forecasted to partly to mostly cloudy with a chance of rain/snow showers throughout the day into the evening. Winds will be 10-20 mph with locally higher gusts and temperatures will be in mid 20Fs to mid 40Fs depending on elevation. 

This variable showery weather pattern looks to persist for the next couple of days as a series of small low pressure systems rotate off of a 'parent low' in the Gulf. There is the potential for a break and clearing on Thursday. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 34  2?  0 119 
Summit Lake (1400')  35  37
Alyeska Mid (1700')  35  1 .1   103

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 25   ENE  25 57 
Seattle Ridge(2400')  28  ESE 14  38

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: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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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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