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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Friday, March 4th 2016
Created: Mar 4th 4:12 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'
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Silverton Mountain Guides
Special Announcement

Due minimal snow coverage and signs of snowmachine impact to exposed vegetation the Seward Ranger District officially closed the Primrose Trail access to Lost Lake yesterday, March 3, 2016.  Thanks to many of you who have made an effort to stay on the trail and to educate others about the consequences of tearing up the vegetation. Until this area recieves more snow the trail will remain closed. 

 


The Bottom Line

Overall generally stable avalanche conditions exist in the advisory area but with the widespread glide cracks in popular recreation terrain in the Treeline (1000'-2500') elevation band and the possibility of triggering a large cornice fall in the Alpine, the hazard remains at MODERATE. In addition, lingering pockets of wind slab and loose snow avalanches may be triggered in steep terrain. Practice safe travel techniques and take inventory of surface conditions as a storm approaches for the weekend.  Watch for changing conditions if snow and winds pick up earlier than forecasted. 


Primary Concern

Glide avalanches continue to release and glide cracks are growing daily. An observer on Wednesday noted movement in the Cornbiscuit glide crack over the course of two ski runs. There was glide avalanche that was observed on south face of Manitoba yesterday that occured sometime between 12 pm-4pm. Glide avalanches are still totally unpredictable and travel underneath glide cracks should be avoided. 

 

 

Recent glide avalanche in the Seattle Creek drainage. This was initially observed Wednesday afternoon and Wendy got a photo of it yesterday.

 

The Cornbiscuit glide crack is huge, growing and scary... It is worth checking out the other photos from the observation on Wednesday. 

Photo: Kevan Dee


Secondary Concern

The cornices are impressive and hang over many slopes in the advisory area. There was a report of a snowmachine triggered cornice fall in Warmup Bowl on Wednesday that took the rider by surprise. They luckily did not go over with the falling chunks of snow. Cornices have the potential to be quite dangerous if you take ride with them or if they fall from above onto you. Avoid travel on top, watch for cornice cracks and limit exposure while traveling below. We are not ruling out the possibility of a large cornice fall triggering an avalanche on the slope below due the massive loading potential. 

 

Snowmachine triggered cornice fall in Warmup Bowl on Wednesday.

 


Additional Concern

Today is a transitional day as we say goodbye to the sunshine and the clouds move in with the possibility of snow showers. Depending on the thickness of the cloud cover we may still see some surface warming of the snowpack. We have had no reports of human triggered avalanches in the past few days. There is still the possibility of triggering lingering wind slabs in steep leeward terrain, especially unsupported convex slopes. If you are out in the mountains it is worth checking out surface conditions, as these will be what the next wave of snow hopefully bonds to. Southerly slopes have a crust; there have been reports of small surface hoar formation in some areas and in protected areas loose snow is starting to facet. In addition there is a wide array of wind-affected snow at higher elevations and a delightful rain crust lower down.

Loose snow avalanches: Steep protected areas have loose snow that may be enough to push you off your feet if it gains enough force and mass as it travels down slope with you. Manage your sluff by moving out of its path before it hits you.

 

Surface conditions at Turnagain pass.


Mountain Weather

Yesterday was clear and sunny. There were some patches of valley fog. Temperatures were in the mid 20Fs to upper 30Fs. The winds were light and easterly. Temperatures dropped into the high teens to mid 20Fs overnight.

Today will be mostly cloudy with a chance of snow in the morning, increasing in the afternoon. 0-3" of snow is possible. East winds will be light and temperatures will be in the mid 20Fs to 30Fs. 

Rain and snow showers are forecasted tonight and tomorrow. This pattern will continue through the weekend as a low in the Gulf spins a series of weather systems into the area.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 26   138
Summit Lake (1400') 23 0  42
Alyeska Mid (1700')  25 0 104 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  22  ENE 10  22 
Seattle Ridge(2400')  25

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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