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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Friday, April 1st 2016
Created: Apr 1st 4:13 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.
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.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
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Special Announcement

CNFAIC is going to Arctic Man for the fifth year in a row! We are excited be there all week and to offer two FREE companion rescue workshops. Click HERE for more information. We hope to see you there! Stop by the blue trailer and practice in the beacon park! Don't forget your beacon, shovel and probe!

 


The Bottom Line

The avalanche danger is MODERATE today due to above freezing temperatures, rain and an active glide avalanche cycle. Human triggered wet loose avalanches are possible in steep mid-elevation terrain (1000'-2500'). Triggering a fresh wind slab or cornice fall is possible in the Alpine. Avoid being under the runout of glide cracks.

Summer use trails with avalanche terrain above should be avoided due to the threat of natural avalanche activity from above. Byron trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood remains CLOSED for the winter.

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


Primary Concern

Record high temperatures were seen around the state yesterday and advisory area saw the warmest temperatures of the season to date.

Sunburst, 3800': 41F 

Seattle Ridge, 2400': 44F

Center Ridge, 1880': 57F

Summit Lake 1400': 57F

Alyeska mid mountain, 1700': 48F

Clear skies on Tuesday night that allowed for a surface freeze and winds throughout the day helped keep the natural wet loose activity to minimum despite the warm air temperatures. The building daytime cloud cover across the region also added to the variability of surface warming. In sunny areas there was obvious free water in the snowpack as the day heated up. Last night cloudy skies and rain falling (Center Ridge Snotel recorded an inch of water) will keep the mid-elevation snowpack prime for human triggered wet loose activity on steep slopes. Watch for ski and snowmachine penetration and get off slopes if you are sinking in. Remember once wet snow gets moving it often entrains more snow quickly and can be hard to escape. Yesterday there was a report of skier triggered wet loose avalanche in the Summit area on Butch mountain on a west aspect in the afternoon.

Turnagain Pass from the Center Ridge parking lot. Note the surface reflecting in the sun and the large glide crack on the N face of Cornbiscuit.


Secondary Concern

No glide avalanches were reported yesterday on the warmest day we have had this season. What???....... April Fools! Of course there were glide avalanches reported and observed yesterday. A number of new glide avalanches were observed on Seattle Ridge, in Summit Lake and the Girdwood Valley. We are now trying to track areas to see if glides are releasing in spots without pre-existing cracks. If this is the case steering clear of steep terrain in the mid-elevation band around (not just below) glide cracks may also be advised. Visibility may be limited today and make it harder to see where you are in terrain. We can't stress this message enough: Avoid being under the runout of glide cracks. Avoid being under the runout of glide cracks. Avoid being under the runout of glide cracks. 

Glide avalanche on Seattle Ridge that released sometime between 9 am and 1 pm.

 I am going to include Heather's photo from Wednesday again. I think the glide avalanche hazard on the Seattle Ridge up-track is particularly dangerous. 


Additional Concern

Cornices remain extremely large and perched along many ridgelines.  We haven’t seen an active day of widespread cornice failure yet this season.  This just means they continue to grow and creep closer to failure. New snow and wind as well as the warming temperatures this week could act as a catalysts for cornices to fall.  These features deserve extra space and can break farther back than expected. Keep a wide berth both on ridges and when moving below corniced terrain.

Wind slabs: An inch of water was recorded at the Center Ridge Snotel overnight. This could translate to 5-10" of snow above 3000' in the Alpine at Turnagain Pass. This combined with sustained easterly winds may have formed tender wind slabs on along ridgelines. Watch for cracking in the snow and pay attention to how well the snow is bonding to the surfaces below. 

 


Mountain Weather

Yesterday was a mixture of sun and clouds across the advisory area. The region saw very warm temperatures with highs in the 50Fs @ 1000' and in the 40Fs @ 3000'. Winds blew 20-30 mph from the east with gusts into the 50s. Skies clouded up overnight and there were rain showers with the precipitation favoring Turnagain Pass.

Today will be mostly cloudy with continued rain showers and easterly winds 20-35 mph. Temperatures will be in the mid 30Fs to mid 40Fs.

This overall pattern of showers and cloudy skies will persist through the weekend. There is slightly cooler air moving over the forecast area but temperatures will still be above normal. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 45   0 1.1 121 
Summit Lake (1400')  43  0 41 
Alyeska Mid (1700')  42  0  .1 107 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 39  ENE  26  54 
Seattle Ridge(2400') 41  SE   26 54 

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 15, 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

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
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