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Turnagain Area Avalanche Advisory
Friday, January 22nd 2010 6:05 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 Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday January 22nd 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
There are still spots available for tomorrow's snowmachine avalanche workshop in Turnagain Pass. Sign up at the Alaska Avalanche School (alaskaavalanche.com) or call (907)345-0878. They will cover rescue procedures and snow assessments with some class room and lots of field work.

Our Summit Lake Area Advisory is debuting today. It will be a general advisory posted on Friday and Saturday morning. The Summit Lake Area is part of the Chugach National Forest, it has been a goal of the CNFAIC to include more of the Forest for 9 years. Check it out !

WEATHER ROUNDUP
Hindcast (Last 24 hours)

3800 -Sunburst Wx Station-
Current temp is 24 (2 degree warmer than yesterday) Winds have been light averaging 8mph out of the east with a gusts of 14-16 mph. The winds are increasing slightly this morning.

2400-Seattle Ridge Wx Station-
Winds have been calm to light averaging 5 mph out of the NNW with gusts of 7-14. We are currently replacing the temperature sensor on this station.

1800-Center Ridge Wx Station-
Current temp is 17 (2 degrees warmer than yesterday) Zero inches of water and zero inches of new snow has fallen. Total snowpack is 67".

Temps are a couple of degrees warmer this morning with inversions from G-Wood to Summit Lake. Expect 5-12 degrees temperature inversions this morning. These inversions are a sign of a stable air mass. There is a better chance that they will mix out today with increasing winds. The winds will be driven by the 1000 mb -986 mb pressure gradient that exists over our area. Scattered showers on the radar and satellite this morning. Expect clearing skies for the weekend as a weak low pressure trough exists from Central AK to CA.


Forecast

AKZ125-230100-
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST FRI JAN 22 2010

...STRONG WIND THROUGH THIS AFTERNOON NEAR WHITTIER...

.TODAY...CLOUDY WITH SCATTERED SNOW SHOWERS IN THE MORNING...THEN
PARTLY CLOUDY IN THE AFTERNOON. HIGHS IN THE LOWER 20S TO MID
30S...COLDEST INLAND. VARIABLE WIND 10 MPH EXCEPT NORTH WIND 20 TO
35 MPH NEAR SEWARD AND WEST 30 TO 45 MPH NEAR WHITTIER.
.TONIGHT...MOSTLY CLEAR. LOWS IN THE LOWER TEENS TO UPPER 20S...
COLDEST INLAND. VARIABLE WIND TO 10 MPH EXCEPT NORTH AND WEST WIND
20 TO 35 MPH NEAR SEWARD AND WHITTIER.
.SATURDAY...MOSTLY SUNNY. HIGHS IN THE LOWER 20S TO LOWER 30S...
COLDEST INLAND. LIGHT WINDS EXCEPT NORTH AND WEST 15 TO 30 MPH NEAR
SEWARD AND WHITTIER.
.SATURDAY NIGHT...PARTLY CLOUDY. LOWS IN THE LOWER TEENS TO LOWER
30S...COLDEST INLAND. LIGHT WINDS EXCEPT NORTH 15 MPH NEAR SEWARD.
.SUNDAY...MOSTLY SUNNY WITH ISOLATED SNOW SHOWERS. HIGHS IN THE
LOWER 20S TO MID 30S. VARIABLE WIND 10 MPH EXCEPT NORTH 10 TO 15 MPH
NEAR SEWARD.
.SUNDAY NIGHT...MOSTLY CLOUDY WITH ISOLATED SNOW SHOWERS. LOWS
15 TO 25.

TEMPERATURE / PRECIPITATION

SEWARD 29 18 28 / 40 0 0
GIRDWOOD 20 11 18 / 20 0 0

AVALANCHE DISCUSSION

The main avalanche concern continues to be the slippery rain crust underneath the 1.5-2.5 feet of newer snow especially between 2000-3000. This slippery rain crust formed on Thursday Jan 7 and is widespread on all aspects from Girdwood to Seward.

We have been seeing a common feature in the snowpack throughout the advisory area. The newer storm snow likes to fail about inch above the top rain crust with hard failures in the lower 20 range on compression tests with clean shears (Q2) where the shear plane is smooth but does not slide readily.

What this means according to the avalanche guidelines is that these test scores generally indicates good stability (in these particular test pit locations) but a compact group of skiers/snowboarders, a snowmachine, or explosives may trigger an avalanche. Natural avalanches are rare.

These test scores are still on the low end of good stability and the structure of the snowpack is poor right now because it has the three main ingredients for an avalanche: a slab (the new 1.5-2.5 feet of snow) on top of a weaker layer (last weeks 6 inches of light dry snow) on top of a slippery bed surface (rain crust). Parts of our current snowpack and this advisory point toward low avalanche danger. However, I think of it like this. The danger scale only has one more level below our current rating of moderate. I know that stability could be better, thus I'm reserving the low for such a snowpack. Also, Lisa got a RB2 Q1-2 on a reuschblock yesterday at 2000 ft. (RB2=failure occurred when person stepped onto the block, Q1-2 means it had a very clean sheer). Don't let the weather and snow quality shut off your brain this weekend.

Terrain management is key right now. If big lines are on your agenda-keep big eyes wide open. Make good risk assessments, travel one at a time, watch your partner, have an escape route, use terrain that avoids terrain traps, and have a rescue plan with all the rescue equipment needed for companion rescue. In the backcountry you are the rescue party. When responding to avalanche burials, organized rescue is organized recovery.

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 Saturday January 23rd.

 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 20, 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: 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: ClosedClosed as of 3.20.19 due to lack of snow.
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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