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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Thursday, April 7th 2011
Created: Apr 7th 7:02 am
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Treeline / 1,000'-2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Below Treeline / Below 1,000' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
 Show the Complete North American Avalanche Danger Scale
SLR Consulting
The Bottom Line
Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Thursday, April 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).

BOTTOM LINE
Todays avalanche danger rating is rapidly increasing towards HIGH danger. Its an easy day for decision making. Backcountry travel in the alpine is not recommended.

AVALANCHE DISCUSSION
Yesterday was quite active in the backcountry. You had to be perceptive to notice the clues unless you happened to spring a loaded slope as several people did.

There were several avalanches yesterday including naturals, snowmachine, and skier triggered events. Some of those were remotely triggered including the one below from 400 feet away on Tincan. Collapsing (whoomphing) was evident if you happened to be breaking trail or ventured off an established trail.
590-yes_2011_Apr_06_2044-2.jpg


The most significant event was a full burial of a ski guide in the Placer/Skookum region. The guide was working on stability assessment when the slope broke. The victim took a 500 foot ride, deployed an airbag, and was still fully buried 4 feet deep. The contributing factors to a successful outcome were fast action by the rescuers, a path clear of rocks, and the victim deliberately holding his backpack strap and jacket collar to facilitate an air pocket. This avalanche happened on a SW aspect at 3500 feet during mid-day yesterday. The suspected weak layer is buried surface hoar from late March.

Based on the distribution of the known avalanches yesterday (Girdwood to Johnson Pass), I think most of our region above tree line will be dangerous over the next few days. The avalanches happened on all aspects having no discrimination between sun and shade.

The snow structure responsible for our current problems is a number of crusts on the sunny aspects with some buried surface hoar mixed in. Shaded North aspects wont have the sun crusts but the buried surface hoar is larger and weaker. Take a look at this pit from yesterday and CNFAIC Staff recent pits and pictures in the photo gallery.

The mega storm coming in today will probably keep most folks out of the backcountry. I am worried about what might happen when this storm breaks. The snowpack will need time to adjust to the new load. Expect touchy conditions for at least 48 hours after the storm ends and possibly longer.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP
Sunny skies broke yesterday with temperatures just warm enough to wet the south faces. Today a large storm is moving through the region. 6-12 inches of snow is expected for Turnagain Pass with SE wind 50-70 mph today. Snow and wind is expected to diminish tonight. The radar is currently showing the image below.

591-precip.jpg


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 AKDT THU APR 7 2011
...STRONG STORM SYSTEM IMPACTING MUCH OF THE STATE TODAY...

A DYNAMIC AND DANGEROUS STORM HAS MOVED INTO THE CENTRAL BERING SEA
WITH A STRONG FRONTAL BOUNDARY APPROACHING THE NORTH GULF COAST.
LIGHT SNOW HAS BEEN FALLING EARLY THIS MORNING ACROSS THE ANCHORAGE
BOWL AS WINDS CONTINUE TO INCREASE ALONG TURNAGAIN ARM AND THE
HILLSIDE. HEAVIER SNOW IS FALLING NEAR GIRDWOOD WHERE APPROXIMATELY 5
INCHES HAS ALREADY BEEN OBSERVED THIS MORNING. THE COMBINATION OF
SNOW AND GUSTY WINDS ALONG TURNAGAIN ARM IS RESULTING IN HAZARDOUS
DRIVING CONDITIONS.


...HIGH WIND WARNING IN EFFECT UNTIL 4 PM AKDT THIS AFTERNOON FOR
PORTAGE VALLEY AND ALONG TURNAGAIN ARM...
.TODAY...SNOW...BECOMING MIXED WITH RAIN AT TIMES AFTER NOON. AREAS
OF BLOWING SNOW. SNOW MAY BE HEAVY AT TIMES IN THE MORNING. SNOW
ACCUMULATION 2 TO 8 INCHES...GREATEST AMOUNTS THROUGH TURNAGAIN PASS.
HIGHS IN THE MID 30S TO LOWER 40S. SOUTHEAST WIND 10 TO 25 MPH WITH
LOCAL GUSTS TO 35 MPH. THROUGH PORTAGE VALLEY AND TURNAGAIN
ARM...EAST WIND 60 TO 75 MPH BECOMING SOUTHEAST AND DECREASING TO 45
TO 60 MPH LATE IN THE AFTERNOON.
.TONIGHT...NUMEROUS RAIN AND SNOW SHOWERS. SNOW ACCUMULATION
UP TO 1 INCH. LOWS IN THE MID 20S TO MID 30S. SOUTH WIND 10 TO
25 MPH EXCEPT SOUTHEAST 30 TO 45 MPH THROUGH PORTAGE VALLEY AND
TURNAGAIN ARM.
.FRIDAY...SNOW AND RAIN SHOWERS. SNOW ACCUMULATION UP TO
3 INCHES. HIGHS IN THE MID 30S TO NEAR 40. SOUTHEAST WIND 10 TO
20 MPH EXCEPT SOUTHEAST 25 TO 40 MPH THROUGH PORTAGE VALLEY AND
TURNAGAIN ARM.

TEMPERATURE / PRECIPITATION

SEWARD 42 35 40 / 100 70 100
GIRDWOOD 39 28 40 / 100 70 80


WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
Currently 17 degree. Wind gusting to 38 from the East.
-2600 Seattle Ridge Wx Station-
22 degrees at 6am. SE wind to 44mph.
-1800 Center Ridge Wx Station-
25 degrees at 6am. Snow has started to fall.


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

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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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