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Avalanche Advisory

Turnagain Area Avalanche Advisory
Friday, January 18th 2013 6:18 am by John Fitzgerald
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The hazard above treeline today is MODERATE, where it is still possible for a person or snowmachine to trigger a large destructive avalanche.  Below treeline the hazard is LOW today, where it is unlikely for humans to trigger avalanches.  Remember that 'LOW' does not mean 'NO'. The main concern below treeline is being under large, open terrain that has the potential to produce high volume avalanches that can run into the lower elevations.


 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.
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.
Avalanche Problem 1

Deep slab avalanches are the primary concern for today.  Large, dense and potentially deadly slabs continue to sit on a weak foundation.  Clear and cold weather for much of October, November and the first half of December created thick layers of weak, faceted snow.  The steady stream of moisture beginning around Christmas formed the deep slab that we are worried most about.

At this point, it is getting more and more difficult to trigger these avalanches.  But make no mistake; getting tangled up in one of these avalanches has the potential to do a lot of damage.  It is common for this type of avalanche problem to lay dormant for extended periods of time.  It has been 4 days since any natural avalanche activity and 3 days since any human or explosively triggered avalanches have been reported.  With clearing skies and good visibility it will be tempting to venture onto steep terrain.  Do not forget what is down below your feet or sled-weak rotten snow capable of producing very large avalanches.  It is unlikely that the normal warning signs of recent avalanches, shooting cracks or collapsing will be present prior to a deep slab avalanche releasing.

Pit tests over the last several days continue to illustrate this problem well.  The weak layer is hard to impact, but the outcome once it is affected translates to large avalanches propagating across wide areas.


Avalanche Problem 2

Very small shallow (<6") wind slabs formed yesterday in the higher elevations, where light density snow was easily transported by light to moderate winds.  We witnessed very small shooting cracks in the surface snow above treeline yesterday.  While this problem is relatively minor, it is worth paying attention to today in upper elevation starting zones.


Mountain Weather

Precip, winds and temps have not done anything dramatically in the past 24 hours to change our avalanche problems for today.
Light veering winds overnight have given way to current temps in the single digits at ridgetops and mostly clear skies.  No new snow has been recorded in the past 24 hours around Turnagain Arm.
The weather for today looks to be partly cloudy and cooler, with winds out of the NW at 5-15 mph, temps in the teens and no precip expected.
The extended outlook is calling for the next chance of snow on Saturday, as a low pressure system to our SW moves towards the region.

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Kevin will issue the next advisory tomorrow morning, January 19th.

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: May 06, 2018 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed as of April 20th
Placer River: ClosedClosed as of April 17th
Skookum Drainage: ClosedClosed as of April 1st.
Turnagain Pass: ClosedClosed as of May 7th. Happy summer, see ya when the snow flies!
Twentymile: ClosedClosed as of April 13th
Seward District
Carter Lake: ClosedClosed as of 4/27
Lost Lake Trail: ClosedClosed as of April 13th
Primrose Trail: ClosedClosed as of April 13th
Resurrection Pass Trail: ClosedClosed as of April 20th
Snug Harbor: ClosedClosed as of 4/27
South Fork Snow River Corridor: ClosedClosed as of April 13th
Summit Lake: ClosedClosed as of April 20th

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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