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Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, November 24th, 2012 - 7:00AM
Expires
Sun, November 25th, 2012 - 7:00AM
Forecaster
Kevin Wright
The Bottom Line

We are issuing advisories 5 days a week through November on Sat, Sun, Tue, Thur and Fri.

BOTTOM LINE

Cold temperatures and no significant precipitation in several days is leading to a slow decrease in the avalanche danger.  Pockets of stiffer slab over very weak facets at the ground still create the avalanche recipe in specific places.  Conservative terrain management is still advised.  Below treeline is generally LOW avalanche danger.  

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Sat, November 24th, 2012
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Low (1)
Avalanche risk
Below Treeline
Below 1,000'
Low (1)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Moderate (2)
Treeline
1,000'-2,500'
Avalanche risk
Low (1)
Below Treeline
Below 1,000'
Avalanche risk
Low (1)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at Avalanche.org

If I could relabel the icon on the left as “Persistent Weak Layer”, it would tell the story a bit more accurately.  Faceted snow at the ground is still the culprit, but the overlying snow is also slowly rotting away in our colder temperatures.  This means the former slab over the persistent weak layer is degrading into “weak layer over weak layer”.  Everything is faceting, getting weaker, and losing the potential to propagate into destructive avalanches.  Check out a pit profile from yesterday HERE.

However, we are still finding pockets that will collapse or “whoomph” when you set your own skin track.  This indicates enough of a stiffer slab component to collapse as a unit.  Any areas that show this sign should be considered for avalanche potential.  We found whoomphing on the lee side of a wind loaded ridge yesterday, which convinced us to go elsewhere.  We know that recent avalanches have happened without human influence.  Despite evidence of better stability, I’m not ready to tell myself that I can outsmart the current problem.  

The best way to manage terrain this weekend is to monitor slope angles and keep it less than 35 degrees.  All the recent avalanche activity (HERE, HERE and HERE) has happened on steeper slopes, so this should be an effective strategy.  The picture below shows 2 recent avalanches on Sunburst, and illustrates the terrain that is likely to harbor more avalanche potential.  

Weather
Sat, November 24th, 2012

We continue to be locked into a clear and cold weather pattern.  A 30 degree temperature inversion is showing on weather stations this morning, with comfortable temperatures in the 20s at the ridgetops.  Weather models are showing some kind of pattern change early next week.  


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).  

Wendy will issue the next advisory Sunday morning, November 25th.  

Observations
Recent Observations for Turnagain Pass
Date Region Location
05/06/20 Turnagain Avalanche: Pastoral Peak, north face
04/10/20 Turnagain Avalanche: Wolverine
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04/04/20 Turnagain Observation: Tincan
04/04/20 Turnagain Observation: Pete’s North
03/26/20 Turnagain Avalanche: Tincan – Proper (SW facing)
03/26/20 Turnagain Avalanche: Seattle Ridge
03/25/20 Turnagain Avalanche: Sunburst Uptrack @ 2000′
03/24/20 Turnagain Observation: Turnagain – Road Observations
Riding Areas
Updated Fri, May 01st, 2020

Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: mailroom_r10_chugach@fs.fed.us

Area Status Weather & Riding Conditions
Glacier District
Johnson Pass
Closed
Placer River
Closed
Skookum Drainage
Closed
Turnagain Pass
Closed
Closed as of May 1. Thanks for a fun, safe season!
Twentymile
Closed
Seward District
Carter Lake
Closed
Lost Lake Trail
Closed
Primrose Trail
Closed
Resurrection Pass Trail
Closed
Snug Harbor
Closed
South Fork Snow River Corridor
Closed
Summit Lake
Closed

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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.