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Turnagain Area Avalanche Advisory
Tuesday, January 12th 2010 7:05 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 12th 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).


ANOUNCEMENTS
Thanks to the group that removed the snowmachine jump on the motorized side of the highway so quickly.


WEATHER ROUNDUP
Hindcast (Last 24 hours)

3800 -Sunburst Wx Station-
Temperatures ranged between 9 to 23 degrees F with light average winds between 3-13 out of the ENE with a light max gust of 16 mph. Current temp 14.

2400-Seattle Ridge Wx Station-
Winds have been light averaging 1-6 mph out of the N with a light max gust of 10mph

1800-Center Ridge Wx Station-
Precip: 0.1 inches of water and 1 of new snow
Total depth of 56 inches
Temperatures ranged between 3-10 degrees F
Current temp 10

Nowcast

Temps are have increased at all wx stations this morning by 3-7 degrees. There is a slight inversion this morning with warmer temps on the ridgelines compared to the valley floors. Winds are starting to increase to the north and south of Turnagain Pass but are still only averaging light to moderate. Precip totals are consistent at all wx stations with about .1 inch of water and 1 of new snow. The Middleton radar shows moderate but scattered precip over PWS moving west toward Turnagain Pass, and there is light precip on the Kenai radar moving west over Turnagain Pass. Its currently snowing lightly in Girdwood with about 1 inch accumulation

Forecast

WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST TUE JAN 12 2010

...STRONG WIND THIS MORNING NEAR SEWARD...
.TODAY...SNOW. SNOW ACCUMULATION 2 TO 5 INCHES. PERIODS OF BLOWING
SNOW NEAR SEWARD AND WHITTIER. HIGHS IN THE MID TEENS TO LOWER
30S...COLDEST INLAND. NORTH TO WEST WINDS 5 TO 15 MPH. GUSTS TO 25
MPH NEAR WHITTIER THIS MORNING. NEAR SEWARD...NORTH WINDS 15 TO 25
MPH WITH GUSTS TO 50 MPH THROUGH EARLY THIS AFTERNOON.
.TONIGHT...SNOW LIKELY. SNOW ACCUMULATIONS 2 TO 4 INCHES. LOWS 15 TO
25. VARIABLE WIND 10 MPH EXCEPT NORTH 10 TO 20 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 28 25 32 / 80 60 40
GIRDWOOD 22 21 29 / 80 40 40

Short Term Weather Models (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass
Sea-level: GFS shows 0.5 inches of water forecasted today, but the WRF shows the majority of precip tapering off by 9am with the majority of the precip southwest of Seward.
3000: temps forecasted between 23 and 32 degrees F with winds 10-15mph
6000: temps forecasted between 14 and 23 degrees F with winds 25-30mph



AVALANCHE DISCUSSION
Today's weather could contribute to the avalanche danger today at Turnagain Pass if the weather picks up; however, not enough weather has happened yet (as of this morning) to increase the danger. The NWS is calling for strong wind mostly south of Turnagain Pass. The models only show about an inch of water; so, the forecasts dont look like this storm is going to pack too big of a punch.

Todays avalanche danger will remain at LOW with the potential for some small wind slabs later this afternoon. LOW is defined as: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human triggered avalanches unlikely (except glide cracks are possible). Small avalanches in isolated areas of extreme terrain.

In simple terms, we have a variety of weak layers below 2800 and one weak layer at higher elevations between 2800 up to the ridgelines.

The big picture right now is the rain crust that formed up to 2800 has a lot of potential to become a very dangerous weak layer in the future. This will be to first bad weak layer at a higher elevation that we have seen all season (except for the facets on the ground in the early season). Turnagain Pass has plenty of terrain steep enough to avalanche at 2800 including the bowls along Seattle Ridge. Its difficult to say exactly how this rain crust will react to new snow on top; so, we all need to take it easy once the next big storm comes in.

The wild card right now are the glide cracks. One of these crevasse like features avalanched last week for no obvious or apparent reason (see photo gallery). Nostradamus couldnt have predicted that one; so, it adds to the theory that glide cracks are like cornices in that they are very difficult to predict. Sometimes they avalanche when its cold, sometimes when its warm, sometimes when it rains. We have not seen or had any reports of any more glide crack failures in the past week, but it would still be wise to avoid traveling on, near, or underneath the path of any glide cracks.

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 13th.

 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
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