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Turnagain Area Avalanche Advisory
Wednesday, December 16th 2009 7:07 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 Wednesday December 16th 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
All areas designated for snowmachines (except Placer and 20 Mile) on the Chugach National Forest are open. Please remember that Center and Divide Creek near the Johnson Pass Trailhead are always closed due to the current Forest Plan. These areas are periodically patrolled by law enforcement. We are monitoring the snow at Placer and 20 Mile and will open those areas as soon as there is enough snow, these colder temps down low are really helping these areas.


WEATHER ROUNDUP
Will recent weather effect avalanche conditions today?
Well, lets take a closer look at the precip, winds, and temps.

Hindcast (Last 24 hours)

3800 -Sunburst Wx Station-
Temperatures have been dropping from 20-15 degrees with calm winds averaging 1-10 mph from variable directions with a light max gust of 17 mph

2400-Seattle Ridge Wx Station-
Winds have been calm averaging 0-5 mph from variable directions with a calm max gust of 5 mph

1800-Center Ridge Wx Station-
Precip: 0.1 inch of water and 2 inches of new snow
Total depth of 56 inches
Temperatures have been dropping from 22-12 degrees F

Yesterday's snow stake totals
Eddies Lot: 3" new
Motorized Lot: 4" new
Sunburst Lot: 5" new
Johnson Pass North Lot: 4" new

*These parking lot totals show a bit more snow than was recorded by the Center Ridge wx station yesterday morning which reported 2".


Nowcast

Light snow is falling in Girdwood as of 5am. The Middleton radar shows moderate precip moving north mostly over PWS and Cordova and the Kenai radar shows light precip moving north toward Anchorage. Temps are 3-10 degrees colder at most wx station with temps ranging from 18 degrees at sea-level to 15 degrees at 3800'. Winds are calm to light at all ridgetip wx stations this morning.

Forecast

WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST WED DEC 16 2009

.TODAY...SNOW. SNOW ACCUMULATION UP TO 3 INCHES EXCEPT 6 TO 12
INCHES FROM WHITTIER TO GIRDWOOD. HIGHS 15 TO 25. VARIABLE WIND
TO 10 MPH. NEAR SEWARD...NORTH WIND TO 15 MPH SHIFTING TO SOUTH
15 TO 25 MPH IN THE AFTERNOON.
.TONIGHT...SNOW IN THE EVENING FROM WHITTIER TO GIRDWOOD WITH
UP TO 4 INCHES ADDITIONAL ACCUMULATION. CNFAIC StaffWISE...SCATTERED
SNOW SHOWERS. LOWS 5 BELOW TO 15 ABOVE...COLDEST INLAND. SOUTH
TO EAST WIND TO 15 MPH.
.THURSDAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS
5 TO 15 ABOVE. VARIABLE WIND TO 10 MPH. NEAR WHITTIER AND
SEWARD...LIGHT WINDS BECOMING NORTH TO WEST 15 TO 30 MPH IN
THE AFTERNOON.

TEMPERATURE / PRECIPITATION

SEWARD 23 11 12 / 70 40 40
GIRDWOOD 17 10 12 / 100 80 60

Short Term Weather Models (NAM) (MM5) for the Kenai Mountains near Turnagain Pass
Sea-level: 0.0 - 0.25 inches of water forecasted today
3000: temps forecasted below freezing today around 14-23 degrees F with calm winds 5-10mph
6000: temps forecasted below freezing today around 5-14 degrees F with light winds 10-15mph

AVALANCHE DISCUSSION
The weather should not contribute significantly to the avalanche danger today at Turnagain Pass. The NWS and weather models directly over Turnagain Pass are not forecasting much wind for the Turnagain Pass area. Plus the models really jive with the NWS forecast because they show most of the precip between Whittier and Girdwood and not in the Kenai Mountains.

Due to insignificant results in recent snow stability test pits, zero significant natural or human-triggered avalanches reported or observed recently, and a lack of wind forecasted from the NWS, todays avalanche danger level will remain at LOW. LOW is defined as: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human-triggered avalanches unlikely. Very small avalanches in widespread areas; or small avalanches in isolated areas.

Normal Caution is advised.

The next avalanche concern that we are watching out for is on the current surface snow. There are widespread firm or slippery surfaces created by the wind, sun, and warm temps from last week. Surface hoar formed from sea level to as high as 2800', however, the most defined surface hoar and faceted surface snow is below 1600'; so, due to the slippery surfaces and formation of surface hoar and faceted sugary surface snow, the worst weak layer in the near future will be below 2800'. These mid to lower elevations could become our next big problem when we get the next big weather event. Just as a reminder, most of the bowls along Seattle Ridge are below 2800'. CNFAIC Staff areas with steep terrain below 2800' include but are not limited to the lower part of Eddies, Pete's North, and the terrain behind the "Welcome to the Kenai" sign near Pyramid along Seattle Ridge.

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

Thanks for checking todays avalanche advisory. The next one will be posted tomorrow Thursday December 17.
 Show the Complete North American Avalanche Danger Scale
0 NO RATING Alpine / Above 2,500'
0 NO RATING Treeline / 1,000'-2,500'
0 NO RATING Below Treeline / Below 1,000'

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

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
© 2019 Chugach National Forest Avalanche Information Center. All rights reserved.
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