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Turnagain Area Avalanche Advisory
Tuesday, January 5th 2010 7:00 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 January 5th 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
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 increasing from 23 to 26 degrees F with light to moderate winds averaging 5-23 mph from the E with a strong max gust of 42 mph

2400-Seattle Ridge Wx Station-
Winds have been light to moderate averaging 9-26 mph from SE with a max gust of 39 mph

1800-Center Ridge Wx Station-
Precip: 0.0 inches of water
Total depth of 57 inches
Temperatures have increased from 30-33 degrees F

Nowcast

A few stars are visible over Girdwood as of 5am. The Middleton radar shows some moderate scattered precip moving north directly over Turnagain Pass, but the Kenai radar only shows light scattered precip. Compared to yesterday, temps are warmer by 1-7 degrees at all wx stations. Temps range 33 degrees F at sea-level to 26 degrees F at 3800'. Winds have backed off a bit since yesterday at most ridgetip wx stations.

Forecast

WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST TUE JAN 5 2010

...STRONG WIND WEDNESDAY MORNING THROUGH WEDNESDAY EVENING
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM...

.TODAY...CLOUDY. PATCHY MORNING FOG. HIGHS IN THE MID 30S
TO LOWER 40S. NORTH TO EAST WIND TO 15 MPH.
.TONIGHT...CLOUDY. LOWS IN THE UPPER 20S TO MID 30S. NORTH
TO EAST WIND TO 15 MPH. GUSTS TO 30 MPH NEAR SEWARD AND
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.WEDNESDAY...A CHANCE OF RAIN AND SNOW IN THE MORNING...THEN
RAIN IN THE AFTERNOON. HIGHS IN THE MID 30S TO LOWER 40S.
NORTH TO EAST WIND 10 TO 25 MPH EXCEPT EAST 35 TO 50 MPH
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

TEMPERATURE / PRECIPITATION

SEWARD 37 32 37 / 0 0 70
GIRDWOOD 37 32 37 / 0 0 70


Short Term Weather Models (NAM, WRF, QPF) for the Kenai Mountains near Turnagain Pass
Sea-level: 0.0-0.1 inches of water forecasted today
3000: temps forecasted between 23 and 32 degrees F with winds 5-10mph
6000: temps forecasted between 23 and 32 degrees F with winds 10-35mph

AVALANCHE DISCUSSION
Today's weather should not contribute to the avalanche danger today at Turnagain Pass. Yesterdays wind was from the normal prevailing direction, and it did not have much snow to transport. We did observe some plumes of snow yesterday, but nothing remarkable. We did not observe any significant wind slab stability problems.

There are two main points of interest in the current snowpack defined by elevation.

1.Below 2200, there is a layer buried surface hoar generally buried about 10-12 inches deep. Plus there is an ice layer at these lower elevations. These could become very dangerous weak layers in the future. Luckily they are confined to lower angle slopes at lower elevations. We will have to be careful at lower elevations in places like Placer Valley if that area ever opens this year. Plus anCNFAIC Staff layer of surface hoar formed with the largest crystals in the bathtub ring where the fog layer was hanging out on the valley walls like the water in a bathtub.

2.Near ridgetops, we continue seeing an instability 6-12 inches deep under the surface. It only shows itself in isolated column stability tests, but it has not been reactive to skis, snowboards, or snowmachines. As of Monday 1/4/09, this layer was reported on Lipps failing with easy to moderate shears in a compression test.

These 2 points of interest are not a problem for todays stability.
Due to a lack of significant weak layers and a mild weather forecast, the avalanche danger for Turnagain Pass will decrease today to LOW. LOW is defined as: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human-triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain.

AnCNFAIC Staff concern today will be the glide cracks. A couple of large glide cracks have opened north of the snowmachine uptrack to Seattle ridge. Odds are there are numerous more of these crevasse like features which may be difficult to see. People and dogs have fallen into these cracks before, and they can be very difficult to get out of. Sometimes these glide cracks will avalanche, but this does not appear to be a concern today. Its always a good idea to treat glide cracks like cornices and avoid traveling underneath their path. Like cornices, glide cracks are very difficult to predict.

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 Wednesday January 6th.

 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: 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

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