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Turnagain Area Avalanche Advisory
Saturday, April 10th 2010 7:14 am by CNFAIC Staff
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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BROUGHT TO YOU BY
The Bottom Line
Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Saturday April 10th, 2010 at 7 am. 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
Skookum Valley and Skookum Glacier are closed to motorized vehicles (snowmachines, helicopters, ATVs) except for subsistence uses.. This closure is directed in the current Chugach National Forest Land and Resource Management Plan. Placer River Drainage remains open for motorized use to Spencer Glacier.

WEATHER ROUNDUP
AnCNFAIC Staff great day yesterday with lots of sun and warm temps. Winds are picking up slightly this morning. The radar shows clear skies at present with a large wave of precip coming in this afternoon. Look for increasing winds and 1-5 inches of snow fall this evening.

AVALANCHE DISCUSSION
Todays avalanche danger will start out as MODERATE, but will rapidly increase to CONSIDERABLE on any sunny slopes when temperatures go above freezing.

Indications that the sun and warming are increasing the avalanche danger include: point release loose snow avalanches on the slopes you are on or adjacent to, sticky or sun effected surface snow under ski, board, or sled, and the softening of any previous surface crusts. These along with that feeling in your gut that this slope is sunny and hot should tell you to get off of avalanche terrain.

The current surface snow has not yet been tested by significantly warm temperatures. We will see increased avalanche activity whenever the temperatures reach the high 30's and direct sun is on the slope. We did see lots of point release avalanches again yesterday and some small slabs pop out as a result of the clear skies.

The primary snowpack concern again today is: intense sun and/or warm temps triggering the top 1-3 feet of new snow on top of a buried sun crust on southern aspects. We have 2 out of 3 ingredients necessary for an avalanche:
-A slab (new storm snow)
-A bed surface (slippery sun crust)
The weak layer is the missing ingredient, but that buried sun crust is smooth enough to act as both a bed surface and a weak layer especially if the sun heats up the slab on top.

Glide cracks are secondary concern today. These crevasse like features are those cracks that go all the way to the ground. Avoid traveling underneath these cracks. Glide cracks and full depth release avalanches have been occurring on warm sunny days.

WEATHER FORECAST (National Weather Service)
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKDT SAT APR 10 2010

.TODAY...PARTLY CLOUDY IN THE MORNING THEN BECOMING MOSTLY CLOUDY.
HIGHS IN THE UPPER 30S TO MID 40S. LIGHT WINDS BECOMING SOUTH
TO EAST 10 TO 20 MPH IN THE AFTERNOON...WITH GUSTS TO 30 MPH
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.TONIGHT...A CHANCE OF SNOW IN THE EVENING...THEN SNOW AFTER
MIDNIGHT. SNOW ACCUMULATION 1 TO 4 INCHES. LOWS IN THE MID 20S
TO LOWER 30S. SOUTH TO EAST WIND 10 TO 25 MPH WITH GUSTS TO 35 MPH
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.SUNDAY...SNOW IN THE MORNING...THEN RAIN AND SNOW IN THE
AFTERNOON. SNOW ACCUMULATION 2 TO 6 INCHES. HIGHS IN THE 30S.
SOUTH TO EAST WIND 10 TO 25 MPH WITH GUSTS TO 35 MPH THROUGH
PORTAGE VALLEY AND TURNAGAIN ARM.
.SUNDAY NIGHT...SNOW AND RAIN. LOWS IN THE UPPER 20S TO MID 30S.
SOUTH TO EAST WIND 10 TO 25 MPH.
.MONDAY...SNOW AND RAIN LIKELY IN THE MORNING...THEN A CHANCE
OF RAIN AND SNOW SHOWERS IN THE AFTERNOON. HIGHS IN THE LOWER
TO MID 40S. SOUTH TO EAST WIND 10 TO 15 MPH.

TEMPERATURE / PRECIPITATION

SEWARD 39 32 39 / 0 100 100
GIRDWOOD 39 30 38 / 0 100 100



WEATHER STATION SUMMARY for last 24 hours at TURNAGAIN PASS
3800-Sunburst Wx Station
20 deg F light wind with moderate SE winds

2600-Seattle Ridge Wx Station
21 deg F winds are 11 with gusts in the teens

1800-Center Ridge Wx Station
20 deg F. Total snowpack is 143"

Thanks for checking todays avalanche advisory. Lisa will update this advisory by 0700 tomorrow morning, April 11th.

 Show the Complete North American Avalanche Danger Scale
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.

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: Jan 13, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Open
Placer River: Open
Skookum Drainage: Open
Turnagain Pass: Open
Twentymile: ClosedClosed. Forest Service is monitoring conditions.
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Primrose Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
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
© 2019 Chugach National Forest Avalanche Information Center. All rights reserved.
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