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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Jon Gellings  
Tuesday, March 1st 2011
Created: Mar 1st 6:53 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.
 Show the Complete North American Avalanche Danger Scale
The Bottom Line
Good morning backcountry travelers. This is Jon Gellings with the Chugach National Forest Avalanche Information Center on Tuesday, March 1st 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).

BOTTOM LINE
The avalanche danger is MODERATE for triggering a wind slab at ridgeline elevations. These avalanches are the most possible in steep rocky terrain and cross loaded gullies. Any new avalanche also has the possibility of breaking into old weak layers, creating a larger avalanche.

AVALANCHE DISCUSSION
Wind slabs are still our primary concern today. These features could allow a backcountry traveler to get out onto a steep slope before fracturing above them. Now that these slabs have been sitting in place for a few days, they are likely to be more resistant to initial failure, but if it happens, there could be wider propagation. Many areas have been wind scoured down to crusts, old tracks, and facets, making for poor riding conditions. Searching for softer surface conditions could lead you right into wind loaded terrain. These wind slabs could possibly be triggered in steep rocky terrain, as well as on slopes and in gullies which have been cross loaded.

Our secondary concern is of avalanches breaking into old weak faceted snow, which could produce a much larger avalanche. We can not forget about this instability, even if it is several days or weeks until a new avalanche breaks down to these layers. Areas with an average snow cover of less than 5-6 feet deep are more prone to this type of instability, especially if the slope in question is steep and has been recently wind loaded. These unmanageable hard slabs are likely difficult to trigger, but can break if the right spot is found.

WEATHER ROUNDUP
Winds are unlikely to be strong enough to transport any more snow today, although some areas near Turnagain Arm may see a few snow plumes near ridges. Temperatures look like they will be similar to yesterday, and there is no new precipitation forecasted for today.

ANNOUNCEMENTS
An APU student is conducting a survey on backcountry skiing group dynamics. Click on the link to participate in research on avalanche safety. Click here to take survey

The Forest Service is installing winter use bridges across Granite creek in Turnagain Pass. Be aware of an ice road from the Lyon creek bridge south towards Johnson Pass on the West side of the highway. Heavy equipment will also be used in the area.

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 MAR 1 2011
.TODAY...SUNNY. HIGHS IN THE LOWER 20S TO LOWER 30S. VARIABLE
WIND TO 10 MPH. NEAR SEWARD AND WHITTIER...NORTH AND WEST WIND
15 TO 25 MPH WITH GUSTS TO 35 MPH DECREASING TO 10 TO 20 MPH
IN THE AFTERNOON.
.TONIGHT...CLEAR. LOWS 10 BELOW TO 5 ABOVE EXCEPT IN THE TEENS
ALONG THE COAST. LIGHT WINDS. NEAR SEWARD...NORTH WIND 10 TO 20 MPH.
NEAR WHITTIER...WEST WIND TO 15 MPH WITH GUSTS TO 30 MPH.
.WEDNESDAY...SUNNY. HIGHS IN THE LOWER 20S TO LOWER 30S.
VARIABLE WIND TO 10 MPH. NEAR SEWARD...NORTH WIND 10 TO 20 MPH.
NEAR WHITTIER...WEST WIND 15 TO 25 MPH WITH GUSTS TO 35 MPH.


TEMPERATURE / PRECIPITATION
SEWARD 28 17 27 / 0 0 0
GIRDWOOD 20 5 20 / 0 0 0


WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
(@ 4am) Temperature 12 degrees. NW winds 5-10mph, gusting to 20.
-2600 Seattle Ridge Wx Station-
Temperature 15 degrees. Calm NW winds gusting to 10.
-1800 Center Ridge Wx Station-
Temperature 11 degrees. No new snow.

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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