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Turnagain Area Avalanche Advisory
Thursday, February 25th 2010 6:04 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 Matt Murphy with the Chugach National Forest Avalanche Information Center on Thursday February 25th 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).


WEATHER ROUNDUP
-The winds have been light at all ridge top weather stations but they are starting to pick up a bit this morning with some moderate gusts
-The current radars show scattered precip over PWS moving NE, but a good flow of moderate precip on the Kenai radar moving right toward Anchorage.
-In the last 24 hours (5am-5am), the snotel sites recorded 0 inches of water at Turnagain Pass, 0 inches at Grandview, and 0 at Summit Creek. The total snowpack has settled 1-2 since yesterday
-Temps are colder this morning at all wx stations compared to yesterday. Temps range from 30 degrees F at sea-level and 22 degrees F at 3800. High temps still made it as high as 31 degrees at 3300 yesterday afternoon.


AVALANCHE DISCUSSION
Todays avalanche danger is MODERATE due to the unpredictable nature of glide cracks and cornices. We have had recent glide crack and cornice avalanche activity; so, these types of natural avalanches are possible today. Glide cracks can be easy to avoid because you can see them, but they are difficult forecast. A very small glide crack avalanche was observed on Center Ridge two days ago. CNFAIC Staff than glide cracks and cornices, the snowpack in general is showing good to very good stability. The avalanche danger scale does not fit very well with today's conditions.

The two specific areas of concern today are:
-Glide Cracks
Glide cracks are those crevasse like features in the snow that open up all the way to the ground. The snowpack is starting to pull away from the ground in many locations creating these glide cracks. Glide cracks are very difficult to predict. Sometimes they avalanche when it is cold, sometimes when it is warm, sometimes when it rains, sometimes when it snows. The point is that we are having an active glide crack cycle right now. At least one glide crack avalanche was observed 2/23/2010 below 2000 on Center Ridge. When glide cracks avalanche, they fail all the way to the ground. We also observed a dirty pile of debris on a northern aspect on Tincan Ridge (beyond Todds Run). We were not able to see the origin of that dirty pile, but there is a good chance that it was a glide crack avalanche as well. Avoid traveling underneath or anywhere near glide cracks especially during times that they are actively moving like they are right now.

-Cornices
We received a report of a close call that happened on Monday 2/22/2010 on the cornice above Zero Bowl (No Name Bowl) at the top of the snowmachine up-track on Seattle Ridge. A snowmachiner accidently triggered a chunk of cornice that fractured underneath the ski of his snowmachine. We took a closer look at the cornices along Seattle Ridge from 3000 in Warm-Up Bowl to 2400 in Main Bowl near Widowmaker. We found: several cornice failures, cracks at the roots of cornices that are difficult to see but easy and dangerous to fall into, sagging cornices, and generally much larger cornices than we have seen all year. Be especially careful along ridges with cornices today.

Glide cracks and cornices are total wild cards. Both of these features are very difficult to predict. Since we are seeing recent activity with both of these features right now, this is one of those times to be extra careful anywhere near cornices and glide cracks. Avoid traveling underneath, along the side, above, or anywhere near glide cracks or cornices today.

WEATHER FORECAST (National Weather Service)
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST THU FEB 25 2010

...STRONG WIND FRIDAY MORNING THROUGH FRIDAY AFTERNOON IN WHITTIER...

.TODAY...NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION UP TO 2 INCHES.
HIGHS IN THE 30S. LIGHT WINDS.
.TONIGHT...PARTLY CLOUDY. SCATTERED SNOW SHOWERS IN THE EVENING.
LOWS 15 TO 25. VARIABLE WIND 10 MPH EXCEPT NORTH AND WEST
WIND INCREASING TO 15 TO 30 MPH NEAR SEWARD AND WHITTIER.
.FRIDAY...MOSTLY SUNNY. HIGHS IN THE MID 20S TO LOWER 30S.
VARIABLE WIND 10 MPH EXCEPT NORTH AND WEST WIND 15 TO 30 MPH
NEAR SEWARD AND WHITTIER. GUSTS TO 45 MPH IN WHITTIER.

Temperature / Precipitation

SEWARD 35 22 28 / 40 0 0
GIRDWOOD 32 18 27 / 90 50 0


Short Term Weather Model Forecasts (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass
Sea-level: temps are forecasted between 18-32 and between 0.0-0.1 of water forecasted 3000: temps are forecasted in the range of 23-32 degrees F with winds 5 mph
6000: temps are forecasted in the range of 14-23 degrees F with winds 10-15 mph

WEATHER STATION SUMMARY for last 24 hours at TURNAGAIN PASS
3800-Sunburst Wx Station
Current Temp: 22 (2 degrees colder than yesterday)
Winds: In last 24 hours winds have been light averaging 2-8mph with light gusts up to 11mph. *Note: Wind direction is from unusual direction this morning. Winds are out of the West when they are typically out of the East.

2600-Seattle Ridge Wx Station
Winds: In last 24 hours winds have been light averaging 1-13mph with a moderate gust of 19mph

1800-Center Ridge Wx Station
Current Temp: 25 degrees (5 degrees colder than yesterday)
Precip: 0 new water, 0 new snow, 1 of total snowpack settlement/melting for total snowpack depth of 88

Thanks for checking todays avalanche advisory. The next one will be posted tomorrow Friday February 26th.

 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: Mar 16, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Open
Placer River: OpenVery wet. Travel not recommended until a re-freeze.
Skookum Drainage: OpenNote: The Skookum drainage closes to snowmachines on April 1 annually as per the Chugach NF Forest Plan.
Turnagain Pass: Open
Twentymile: OpenVery wet. Travel not recommended until a re-freeze.
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

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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