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Turnagain Area Avalanche Advisory
Tuesday, February 23rd 2010 7:02 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 Tuesday February 23rd 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 decreased since yesterday, and are currently light at all ridgetop weather stations this morning. Moderate to strong average wind speeds were recorded yesterday averaging as high as 23-27mph with some extreme gusts up to 41 mph.
-The current radars are mostly clear except for some very light precip way out over the Gulf of Alaska.
-In the last 24 hours (4am-4am), 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 and/or melted 1-2 since yesterday
-Temps are 3-6 degrees colder at most wx stations this morning compared to yesterday. Temps range from 30 degrees F at sea-level and 24 degrees F at 3800. *Note temps have remained above freezing at 1800 in Turnagain Pass for the past 5 days with high temps reaching as high as 40 degrees.


AVALANCHE DISCUSSION
Todays avalanche danger will decrease to MODERATE due to time since the last major avalanche cycle and due to a lack of significant weather in todays weather forecast.

Some recent avalanche observations include: the formation of glide cracks, small wind slabs, and a sensitive cornice on Seattle Ridge. The winds have been the biggest factor for avalanches recently, and although they have backed off this morning, be careful along ridges for small isolated avalanches. Additionally, be especially careful near cornices. We received a report of a close call 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.

Although temps at mid elevations have been above freezing for 5-7 consecutive days, the snowpack has not been showing any obvious signs of instability. It has still been getting cold enough for a thin crust to form on top of the wet snow at these elevations. The weather stations have not been showing any drastic changes in the total snowpack depth. The snowpack has only settled/decreased by 1-2 inches in the past 48 hours.

The snowpack is starting to pull away from the ground in many locations creating 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. There have been no reports of any glide-crack avalanches yet, but they are noticeably moving and growing throughout the day. Its always best to avoid traveling underneath or anywhere near glide cracks especially during times that they are actively moving. These crevasse-like cracks in the snow are total wild cards.

WEATHER FORECAST (National Weather Service)
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST TUE FEB 23 2010
.TODAY...MOSTLY CLOUDY. A CHANCE OF RAIN IN THE AFTERNOON. HIGHS IN
THE MID 30S TO LOWER 40S. VARIABLE WIND 10 MPH.
.TONIGHT...CLOUDY WITH A CHANCE OF SNOW. LOWS IN THE MID 20S TO
LOWER 30S. VARIABLE WIND 10 MPH.
.WEDNESDAY...CLOUDY. A CHANCE OF SNOW IN THE MORNING...THEN A
CHANCE OF RAIN AND SNOW IN THE AFTERNOON. HIGHS IN THE 30S. LIGHT
WINDS.
.WEDNESDAY NIGHT...CLOUDY WITH A CHANCE OF SNOW. LOWS IN THE MID
20S TO LOWER 30S. LIGHT WINDS.

Temperature / Precipitation

SEWARD 40 28 38 / 30 60 40
GIRDWOOD 39 28 38 / 0 20 30


Short Term Weather Model Forecasts (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass
Sea-level: temps are forecasted between 28-39 and between 0.0-0.1 of water forecasted
3000: temps are forecasted in the range of 23-32 degrees F with winds 10-15mph
6000: temps are forecasted in the range of 23-32 degrees F with winds 10-15mph

WEATHER STATION SUMMARY for last 24 hours at TURNAGAIN PASS
3800-Sunburst Wx Station
Current Temp: 24 (6 degrees colder than yesterday)
Winds: averaging light at 5mph with light gusts up to 9mph

2600-Seattle Ridge Wx Station
Winds: averaging light at 6mph with light gusts to 10mph

1800-Center Ridge Wx Station
Current Temp: 32 degrees (4 degrees colder than yesterday)
Precip: 0 new water, 0 new snow, 2 of total snowpack settlement/melting

Thanks for checking todays avalanche advisory. The next one will be posted tomorrow Wednesday February 24th.

 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 22, 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: ClosedClosed as of 3/22. Unfortunately HEAVY rain over the past week has washed much of the snow off the lower stretches of this trail.
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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