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Turnagain Area Avalanche Advisory
Tuesday, January 26th 2010 6:59 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 26 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
Hindcast (Last 24 hours)

3800 -Sunburst Wx Station-
Current temp is 27 (5 degrees warmer than yesterday) Winds have been calm to light averaging 0-6 mph out of the WNW with a light max gust of 7 mph

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

1800-Center Ridge Wx Station-
Current temp is 23 (3 degrees warmer than yesterday) Zero inches of water and zero inches of new snow has fallen. Total snowpack depth 64 after 1 of settlement

Nowcast

Temps are warmer at all wx stations this morning by 3-7 degrees. Current temps range from 16 degrees F at sea level to 27 at 3800; so, there is still a slight inversion. There is zero new precip at the snotel sites this morning. Winds are currently calm to light at all ridgetop wx stations this morning. The Middleton and Kenai radars are mostly clear.

Forecast

WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST TUE JAN 26 2010
.TODAY...MOSTLY CLOUDY. PATCHY MORNING FOG. HIGHS IN THE
MID 20S TO MID 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.TONIGHT...MOSTLY CLOUDY. ISOLATED SNOW SHOWERS AFTER MIDNIGHT.
LOWS IN THE MID TEENS TO LOWER 30S...COLDEST INLAND. EAST WIND
10 TO 15 MPH EXCEPT NORTH 15 TO 25 MPH NEAR SEWARD.
.WEDNESDAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN
THE LOWER TO MID 30S. EAST WIND 10 TO 20 MPH EXCEPT EAST 15 TO
30 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

Temperature / Precipitation

SEWARD 30 24 34 / 0 20 50
GIRDWOOD 24 18 33 / 0 0 30

Short Term Weather Model Forecasts (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass
Sea-level: GFS shows a trace of 0.05 inches of water forecasted today
3000: temps are forecasted between 23-32 degrees F with winds 5 mph
6000: temps forecasted between 14-23 degrees F with winds 5 mph


AVALANCHE DISCUSSION
Todays weather should not contribute to the avalanche danger today at Turnagain Pass.

Todays avalanche conditions should be generally safe with a LOW danger rating.

We will most likely not see any major problems till we get more snow or wind. We could have some serious avalanche dangers in the future after the next rapid change with the weather. I know we are starting to sound like a broken record, but the reality is that we still have a poorly structured snowpack with a persistent weak layer up to 3000. This weak layer has not been reactive to any significant avalanches recently. One reason for the lack of avalanches is probably due to the fact that there is not enough of a load on top of it.

My most recent pit near Warm Up Bowl on Seattle Ridge found the same trend that we have been seeing on both sides of the highway. We are still finding moderate-hard failures with smooth shear planes in the lighter density snow slightly above the rain crust. What is very alarming to me is that these test scores are not improving. Usually I will see improved stability on these types of layers over an 8-10 day period. Im not seeing that improvement in my pits, and it seems that CNFAIC Staff folks are getting similar results. The U.S. avalanche observation guidelines classify my pit data as good stability but I have not been seeing what is classified as very good stability yet. That is not much of a problem right now, because there is not enough of a slab on top of this weak layer. That makes me think that we might have some serious problems after the next big storm. The difficulty meter is very high for forecasting this type of avalanche situation.

The main avalanche concern today is that slippery rain crust underneath the 1.5-2.5 powder/newer snow. This slippery rain crust formed on Thursday Jan 7 and is widespread on all aspects up to 3000 from Girdwood to Seward.

A secondary concern exists today below 2000 on facets and surface hoar near the rain crust. This lower elevation problem layer is still showing signs of instability. One of our best observers that is in the mountains all the time in lots of different locations reported, one of the loudest whoomps I have heard in my life when we were climbing out of a gully onto a deposition pillow down in the trees near Tincan on Sunday. This lower elevation weak layer could become a serious problem in places like Placer Valley, where we have steep slopes at lower elevations, especially after the next storm.

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 27th.

 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

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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