Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Thu, February 13th, 2014 - 7:00AM
Expires
Fri, February 14th, 2014 - 7:00AM
Forecaster
Kevin Wright
Avalanche risk The Bottom Line

A few inches of new snow since yesterday will improve the already nice surface conditions around Turnagain pass.  

The main avalanche issues are holding steady – Below 3000 feet the soft snow may slide on a faceted layer above the prominent crust.  Above 3000 feet the soft snow may be stiffer and slabbier, but the presence of a weak interface is less common with the absence of the crust.  

MODERATE  danger is present in areas where wind has built cohesive slabby conditions above treeline.  Below treeline is  LOW  avalanche danger.

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Thu, February 13th, 2014
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

By far the most common problem is related to recent snow on top of the prominent crust layer.  The 16+ inches that Turnagain Pass received on February 7th have been responsible for many reported avalanches since that storm.  The general trend of these avalanches is – small in size (12-20″ deep), lower volume, decent propagation across wind stiffened steep slopes.  Check out the observations page for a bunch of photos from the last 6 days, and this observation for a good quick synopsis of the problem.  

The 2 properties necessary to create avalanches that are not always found –

1.  A cohesive slab – some wind loading and stiffening is necessary to create connectivity of the surface snow, otherwise it’s just loose powder with sluff potential.

2.  A faceted interface between the new snow (Feb 7th storm) and the underlying crust (January melt/freeze) or old snow.  In places where the facets are present, this is a significant weak layer consisting of large loose grains with poor bonding.  

 

Weather
Thu, February 13th, 2014

Cold high pressure from early in the week has transitioned to a showery precipitation pattern as of yesterday afternoon.  A few inches of fresh light powder have fallen since Wednesday.  Temperatures remain quite cold, especially for snow to be falling, reaching into the negatives at many of our local weather stations.  Wind is generally light, although since about 4am the wind has increased slightly and switched over to a East Northeast direction.  Expect cloudy skies today with snow showers and 2-4 inches of snow accumulation today.

The extended forecast looks like more of this same pattern.  A low pressure system is anchored over the northwestern gulf, and expected to stay there well into next week.  Most precipitation from this event will be showery, but there is a chance for heavier snow events by the weekend.  

Observations
Recent Observations for Turnagain Pass
Date Region Location
04/19/21 Turnagain Avalanche: Triangle, Seattle creek
04/18/21 Turnagain Avalanche: Turnagain Pass Road Obs
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04/17/21 Turnagain Avalanche: Road obs
04/16/21 Turnagain Avalanche: Seattle Ridge
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04/12/21 Turnagain Observation: Tincan
Riding Areas
Updated Tue, April 20th, 2021

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
Open
No parking in turnaround at end of the road near the outhouse.
Placer River
Open
Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
Skookum Drainage
Closed
The Skookum Valley is closed to snowmachines. This closure occurs annually on April 1 as per the CNF Forest Plan.
Turnagain Pass
Open
Twentymile
Closed
Seward District
Carter Lake
Open
Lost Lake Trail
Open
Primrose Trail
Open
Resurrection Pass Trail
Closed
Closed for the 2020/21 winter season.
Snug Harbor
Open
South Fork Snow River Corridor
Open
Summit Lake
Open

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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.