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Turnagain Area Avalanche Advisory
Monday, February 1st 2010 6:34 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 Monday, February1st 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 saw light ridgetop winds out of the southeast, mostly cloudy skies, and mountain temps ranging from the upper 20s to mid 30s. As of 4am this morning, ridgetop winds are light with cloudy skies and light freezing rain falling at sea level. Temps currently range from 27F at 3800 feet to 30F at sea level with a band of warmer temps in the low 30s at the mid elevations. Winds will gradually shift to the north today but will remain light while the remnants of a weak low in the gulf will keep skies mostly cloudy. Our spring-like temperatures will gradually fade away this week, but for today, expect only slightly cooler mountain temps in the mid 20s to lower 30s.

AVALANCHE DISCUSSION
Today the avalanche hazard remains at 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 mid-way down leeward slopes. Skier and rider-triggered sluffs are also possible on slopes steeper than 40 degrees.

During our tours up Sunburst and Eddys this past weekend, we found the buried surface hoar that formed January 20-26 buried 4-8 inches deep up to 3500 feet elevation. It failed easily in all of our stability tests but only produced shallow sluffs when ski cut. It is certainly possible the skier-triggered avalanches on Cornbiscuit and Superbowl Peak on Friday failed on this surface hoar layer where it was buried under a thicker slab of windblown snow. It is also possible these slides simply failed on the recently wind-loaded, and thus sensitive, new snow/old snow interface.

We saw no obvious signs of instability this past weekend CNFAIC Staff than skier and rider-triggered sluffs on steep slopes. Numerous groups reported finding stable conditions and felt comfortable skiing and riding steep slopes in the 40 degree range. On direct southern aspects, we saw point-release sluffs and rollerballs from the warm temps and intense solar radiation on Friday and Saturday. Sundays cloud cover kept this to a minimum. 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.

We found the old rain crust that formed January 7 buried 1.5 feet deep on Sunburst and 2-3 feet deep on Eddys. (The crust goes up to 3000 feet elevation on all aspects.) This layer was last reactive 2 weeks ago but continues to produce highly variable results in our snowpits, ranging from no failure at all to easy shears underneath the crust in the 1800 to 2000 ft. range. At 2000 and 2800 feet yesterday on Eddys, we got several hair-raising Q1 shears on top of the crust where we found a thin layer of surface hoar hiding out. Although it took quite a bit of force to get it to fail, the slab popped off the column fast and clean (CTH24,25 and ECTP30+ all Q1s). Check out a video of Matt doing an Extended Column Test on this layer by clicking on the button at the top of this page. I think at this point its going to take quite a shock-load to get this layer to faillike a full-on pineapple express dumping feet of snow with hurricane-force winds type of load.

Safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.

Matt 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 MON FEB 1 2010

.TODAY...CLOUDY WITH SCATTERED RAIN AND SNOW SHOWERS. ISOLATED AREAS
OF LIGHT FREEZING RAIN INLAND THIS MORNING. PATCHY MORNING FOG. HIGHS
IN THE LOWER TO MID 30S. VARIABLE WIND TO 10 MPH. NEAR SEWARD...
NORTH WIND 10 MPH.
.TONIGHT...MOSTLY CLOUDY. ISOLATED RAIN AND SNOW SHOWERS IN THE
EVENING. PATCHY FOG AFTER MIDNIGHT. LOWS IN THE MID TEENS TO LOWER
30S. LIGHT WINDS EXCEPT NORTH 15 MPH NEAR SEWARD.
.TUESDAY...PARTLY CLOUDY. PATCHY MORNING FOG. HIGHS IN THE
UPPER 20S TO MID 30S. LIGHT WINDS EXCEPT NORTH 15 MPH NEAR
SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 35 25 34 / 20 20 0
GIRDWOOD 35 24 33 / 0 0 0


WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
recorded light southeasterly winds yesterday averaging 5-8mph. The current temp is 27F (5 degrees colder than yesterday) with winds averaging 2mph out of the east.

-2600 Seattle Ridge Wx Station-
recorded light southeasterly winds yesterday averaging 5-15mph. Winds are currently averaging 7mph out of the southeast.

-1800 Center Ridge Wx Station-
recorded no new snow in the last 24 hours. The current temp is 32F (1 degree colder than yesterday) with a total snowpack depth of 63 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

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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