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Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, January 14th 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 is CONSIDERABLE above treeline today, where human triggered avalanches are most likely in steep wind loaded starting zones.  Below treeline the hazard is MODERATE, where it is still possible for skiers, riders and snowmachiners to trigger avalanches.


 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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.
Avalanche Problem 1

Deep slab avalanches continue to be our greatest concern.  This most recent load of snow, while dense, is probably not enough to drastically increase the likelihood of triggering these large and destructive avalanches.  The weak layers formed in October and November are now buried 4-10 feet in many areas, and are getting more difficult to impact with the weight of a person or snowmachine. 

Areas to avoid today are trigger points in upper elevation starting zones, where those weak layers are only covered by 1-3 feet of slab.  If you're able to hit one of these spots, the potential for avalanches to propagate across large areas remains very high.  What this means is that the chances of starting one of these avalanches is low to moderate but the consequences are very high.  Human triggered deep slab avalanches in the past two weeks have produced impressive amounts of debris, and still warrant our attention. 


Avalanche Problem 2

With a gradual rise in temps over the past 2 days, we have an "upside down" scenario in the upper layers of the snowpack.  Pit tests at treeline yesterday on Tincan revealed this weakness and showed potential for propagation across slopes.  AKDOT was also able to trigger many avalanches around Bird Flats and Girdwood in the storm snow yesterday.  While the storm snow totals were higher in these areas, the general trend of warming over the past 48 hours is similar in both places.  Expect this problem to resolve itself more quickly than the deep slab problem.


Mountain Weather

In the past 24 hours Turnagain pass has received ~8" of new snow with .8" water.  Winds have been light to moderate out of the East averaging in the teens with gusts to 49 mph.  Temps at 1800' have been around 32 with temps at ridgetops in the mid twenties.
The biggest news in weather is that the forecasted rise in temperature and heavy precip did not come to fruition on Turnagain Pass.  The Girdwood Valley has seen almost twice the amount of precip in the past 24 hrs.
Look for precip to taper off today and temps to start gradually dropping with freezing levels descending to sea level by tonight.
The extended outlook calls for a break in precip later today into Tuesday with snowfall returning by midweek.  Temps will be significantly cooler through the next 3 days.

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Wendy will issue the next advisory tomorrow morning, January 15th.

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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