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Turnagain Area Avalanche Advisory
Sunday, January 31st 2010 6:39 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 Lisa Portune with the Chugach National Forest Avalanche Information Center on Sunday, January 31st 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
No new snow fell in the last 24 hours in Turnagain Pass. Our last snowfall was this past Wednesday and Thursday when 4-6 inches fell along with strong easterly winds. Yesterday was a beautiful day to be in the mountainsblue sky, sunshine, light winds, and temps ranging from the upper 20s to upper 30s. As of 4am this morning, ridgetop winds are light out of the southeast with partly cloudy skies above the dense fog in the arm. We have a more pronounced inversion this morning with temps currently ranging from 32F at 3800 feet to 21F at sea level. A weak low in the gulf will bring mostly cloudy skies today, mountain temps in the upper 20s to low 30s, and light easterly ridgetop winds.

AVALANCHE DISCUSSION
Today the avalanche hazard is LOW with pockets of MODERATE danger on slopes steeper than 35 degrees. Last weeks 4-6 inches of new snow and strong easterly winds created sensitive soft slab that was reactive to skiers as recently as Friday. In some areas this new snow buried a layer of surface hoar that formed up to 3500 feet elevation. The surface storm snow instabilities seem to have lost their reactivity, but it is still possible to find and trigger a pocket of buried surface hoar especially on leeward aspects. Skier and rider-triggered sluffs are also possible on slopes steeper than 40 degrees.

Jon and I toured up Sunburst yesterday and took advantage of the stellar weather conditions by digging seven snowpits with over 25 stability tests at 2000, 2500, 3000, and 3500 feet elevation. We sporadically found the buried surface hoar that formed January 20-26 buried 4-8 inches deep up to 3500 feet. It failed easily in all of our stability tests. It is certainly possible the skier-triggered avalanches on Cornbiscuit and Superbowl Peak on Friday failed on this buried surface hoar layer. It is also possible they just failed on the recently wind-loaded, and thus sensitive, new snow/old snow interface. (Check out our photo gallery for a shot of the Superbowl Peak slide.)

We found the old buried rain crust that formed January 7 down about 1.5 feet on Sunburst. This layer was last reactive 2 weeks ago but continues to produce highly variable results in our snowpits. (CT8,9,11,13,15,29,30++,CTN) The most unstable results are below 2000 feet where we get consistent failures underneath the crust on a thick layer of facets and isolated reports of whumphing.

We saw no obvious signs of instability yesterday CNFAIC Staff than skier and rider-triggered sluffs on steep slopes. On direct southern aspects, we continued to see point-release sluffs and rollerballs from the warm temps and intense solar radiation. Up valley from Tincan Proper in the Library, one of these wet sluffs entrained quite a bit of snow and created a large debris pile on the valley floor. The most recent rain crust that formed 3 days ago is very thin and only goes up to 1600 feet thankfully.

Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.

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.

The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS

500 AM AKST SUN JAN 31 2010

...DENSE FOG ADVISORY IN EFFECT UNTIL NOON AKST SUNDAY...

.TODAY...MOSTLY CLOUDY. AREAS OF DENSE FOG THIS MORNING...MAINLY
ALONG TURNAGAIN ARM. LOCAL VISIBILITIES TO ONE QUARTER MILE OR LESS
AT TIMES THIS MORNING. ISOLATED RAIN AND SNOW SHOWERS IN THE
AFTERNOON. HIGHS IN THE 30S. VARIABLE WIND 10 MPH EXCEPT NORTH 10 TO
20 MPH NEAR SEWARD.
.TONIGHT...MOSTLY CLOUDY WITH SCATTERED RAIN AND SNOW SHOWERS. PATCHY
FOG. LOWS IN THE LOWER 20S TO MID 30S. VARIABLE WIND 10 MPH EXCEPT
NORTH 10 TO 20 MPH NEAR SEWARD.
.MONDAY...PATCHY MORNING FOG. MOSTLY CLOUDY WITH SCATTERED SNOW AND
RAIN SHOWERS. HIGHS IN THE UPPER 20S TO MID 30S. VARIABLE WINDS 5 TO
10 MPH EXCEPT NORTH 10 TO 20 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 35 27 35 / 20 40 40
GIRDWOOD 36 28 34 / 0 0 0

WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
recorded light and variable winds yesterday averaging 1-5mph. The current temp is 32F (same as yesterday) with winds averaging 5mph out of the southeast.

-2600 Seattle Ridge Wx Station-
recorded light easterly winds yesterday averaging 1-10mph. Winds are currently averaging 5mph out of the southeast.

-1800 Center Ridge Wx Station-
recorded no new snow in the last 24 hours. The current temp is 32F (2 degrees warmer than yesterday) with a total snowpack depth of 64 inches.

 Show the Complete North American Avalanche Danger Scale
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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 20, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Open
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: Open
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
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: ClosedClosed as of 3.20.19 due to lack of snow.
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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