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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   CNFAIC Staff  
Sunday, December 5th 2010
Created: Dec 5th 6:26 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
 Show the Complete North American Avalanche Danger Scale
Moose\
The Bottom Line
Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Sunday, December 5th 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).

ANNOUNCEMENTS
Carl Skustad, the Director of the Chugach National Forest Avalanche Information Center, has accepted a promotion and will be moving with his family to Minnesota. Carl created this avalanche center and his leadership will be missed. The Skustads have been an important part of the Girdwood community for over 10 years. Thanks Carl for all your good work here on the Chugach!

WEATHER ROUNDUP
It was a beautiful day of perpetual alpenglow yesterday after 8-14 inches of new snow fell in Turnagain Pass 2 days ago. After the gale force winds on Friday, ridgetop winds yesterday averaged 5-15mph out of the east while mountain temperatures ranged from the upper teens to low 20s. Skies are partly cloudy this morning with mountain temps in the 20s and light ridgetop winds. Today temperatures will be just slightly warmer than yesterday while winds should remain on the light side as well.

AVALANCHE DISCUSSION
Today the avalanche hazard will remain at CONSIDERABLE on steep windloaded slopes greater than 38 degrees while slopes not affected by Fridays wind will have a MODERATE danger. Small to medium sized human-triggered avalanches 1-2 feet deep will certainly be possible on steep windloaded terrain. Use extra caution on steep unsupported convex slopes near ridgetops and in crossloaded gullies.

Fridays storm dumped 8-14 inches of surprisingly light dry snow on top of a layer of surface hoar that formed last week during the clear and cold weather. Underneath the surface hoar is 6 inches of low density faceted snow, which in turn is sitting on the dreaded Thanksgiving Rain Crust. We saw numerous small natural avalanches on the west face of Eddies and on the north side of Cornbiscuit that probably happened at the tail end of the storm. As Jon and I toured up Tincan yesterday we got collapsing and cracking of the snowpack on wind-affected terrain above treelinesure signs of instability. On a small 40 degree test slope at 2500 feet, I triggered a shooting crack 25-30 feet long and 1.5 feet deep that coincided with 2 loud whumphs. The soft windslab failed on the layer of surface hoar 6 inches above the crust. Several snowmachiners also reported triggering small avalanches on steep rollovers.

The persistent nature of buried surface hoar and rain crusts warrants careful route finding skills and conservative decision making about what slopes to ski and ride. 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 windloaded slopes. For the first time in 4 weeks, I saw no new glide avalanches up at the pass yesterday. The new snow is covering up many of the existing cracks that have not avalanched yet, so be extra cautious on your descent.

On a side note, we received a report of several human triggered avalanches in the South Fork area north of Anchorage. A skier in North Bowl ski cut an east facing gully at 3800 feet and triggered a slide 12-18 inches deep that ran 600 feet downhill. As he began to ski cut, he heard a pop just before the entire slope broke under his skis and about 20 feet above him. He was able to ski off of the slab but his dog was swept down slope. Fortunately his dog was not buried. CNFAIC Staff human triggered avalanches were spotted on Three Bowls and Lynx yesterday as well.

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 SUN DEC 5 2010

.TODAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS IN THE
MORNING...THEN PARTLY CLOUDY IN THE AFTERNOON. HIGHS IN THE LOWER
20S TO MID 30S...COOLEST INLAND. VARIABLE WIND TO 10 MPH. NEAR
SEWARD...NORTH WIND 10 MPH INCREASING TO 20 MPH IN THE AFTERNOON.
NEAR WHITTIER...WEST WIND 10 MPH INCREASING TO 20 MPH BY AFTERNOON.
.TONIGHT...MOSTLY CLEAR. LOWS IN THE LOWER TEENS TO LOWER
30S...COOLEST INLAND. VARIABLE WIND TO 10 MPH. NEAR SEWARD...NORTH
WIND 10 TO 25 MPH. NEAR WHITTIER...WEST WIND 20 TO 30 MPH.
.MONDAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN THE
LOWER 20S TO MID 30S...COOLEST INLAND. LIGHT WINDS. NEAR
SEWARD...NORTH WIND 15 TO 25 MPH. NEAR WHITTIER...WEST WIND 20 TO 30
MPH.
TEMPERATURE / PRECIPITATION

SEWARD 32 26 33 / 40 20 40
GIRDWOOD 24 18 24 / 0 20 40

WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
recorded light easterly winds yesterday averaging 5-15mph and temps ranging from 16F to 20F. The current temp is 20F with light winds out of the northeast.
-2600 Seattle Ridge Wx Station-
stopped working yesterday but recorded temps ranging from 19F to 23F. The current temp is 24F.
-1800 Center Ridge Wx Station-
recorded no new snow in the last 24 hours. Temps yesterday ranged from 20F to 24F. The current temp is 25F.

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: Apr 11, 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: OpenWide swaths of open river in the Placer Valley. Travel with extreme caution!
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: ClosedClosed for the remainder of the 2017 season.
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

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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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