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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Jon Gellings  
Tuesday, December 7th 2010
Created: Dec 7th 6:49 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.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
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The Bottom Line
Good morning backcountry travelers this is Jon Gellings with the Chugach National Forest Avalanche Information Center on Tuesday, December 7th at 7am. This will serve as 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).

WEATHER ROUNDUP
If you were able to brave the flat light for a few hours in the morning yesterday, you were rewarded with good viewing conditions in the early afternoon. Our last snowfall was Friday when 8-14 inches fell in Turnagain Pass accompanied by gale force easterly winds. No new snow is showing up on the weather stations, while the mountain temperatures are in the upper 20's to lower 30's. Winds are generally light out of the Northeast, with gusts into the low 20's. Today temperatures will remain in the 20s and low 30's, while winds should stay on the light side as well. We may get anCNFAIC Staff inch or two of snow this morning and afternoon out of a slow-moving front moving west from the gulf, but nothing substantial.

AVALANCHE DISCUSSION
Today the avalanche hazard is MODERATE. Small to medium sized human-triggered avalanches
1-2 feet deep are still possible on steep windloaded slopes. Natural avalanches are unlikely. Use caution on steep unsupported convex terrain near ridgetops and in crossloaded gullies.

Numerous small human triggered avalanches were reported Saturday but nothing since then, while most of our natural avalanches happened late Friday at the tail end of the storm. The culprit is a layer of surface hoar that formed last week during the cold clear weather. Underneath the surface hoar is 6 inches of low density faceted snow, which in turn is sitting on the dreaded Thanksgiving Rain Crust. The new snow in non wind-affected terrain is not slabby enough yet to propagate a fracture, so our primary concern today is mainly on any windloaded slopes up high where the surface hoar and rain crust are buried under a dense slab of snow.

Lisa and I got subtle whumphing on Center Ridge yesterday, where we were trying to maintain the weather station. Two days beforehand, we were getting loud whumphing and 25-30ft. long shooting cracks on a windloaded slope above treeline three days agoobvious signs of an unstable snowpack. One of our observers, however, reported no signs of instability two days ago while snowmachining in Main Bowl on the backside of Seattle Ridge. He also watched a skier on Widowmaker Peak where the new snow only sluffed on the layer of surface hoar.

For the first time in 4 weeks, no new glide avalanches were observed this past weekend. The new snow is covering up many of the existing cracks that have not yet avalanched, so be extra cautious on your descent.

I will issue the next advisory tomorrow morning at 7am. If you get out in the backcountry give us a call at 754-2369 or send us your observations using the button at the top of this page. Thanks and have a great day.

The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST TUE DEC 7 2010
.TODAY...SNOW SHOWERS. SNOW ACCUMULATION UP TO 2 INCHES. HIGHS IN THE
20S TO 30S...COOLEST INLAND. VARIABLE WIND TO 10 MPH EXCEPT NORTH 15
TO 25 MPH NEAR SEWARD.
.TONIGHT...CLOUDY. SCATTERED RAIN AND SNOW SHOWERS IN THE EVENING.
LOWS IN THE 20S. VARIABLE WIND TO 10 MPH. NEAR SEWARD...NORTH WIND 15
TO 25 MPH.
.WEDNESDAY...MOSTLY CLOUDY IN THE MORNING THEN BECOMING PARTLY
CLOUDY. HIGHS IN THE MID 20S TO MID 30S. VARIABLE WIND 10 MPH EXCEPT
NORTH 10 TO 20 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 33 29 31 / 80 40 0
GIRDWOOD 25 24 24 / 60 40 0

WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
recorded light Northeast winds yesterday averaging 5-10mph and temps ranging from 21F to 27F. The current temp is 27F with light winds out of the Northeast.
-2600 Seattle Ridge Wx Station-
stopped working but recorded temps ranging from 21F to 28F yesterday. The current temp is 28F.
-1800 Center Ridge Wx Station-
recorded no new snow in the last 24 hours. Any change in SWE is attributed to a large clump of snow which broke from on top of the tower. Temps yesterday ranged from 21F to 31F. The current temp is 30F.

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

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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