Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Thu, January 24th, 2013 - 7:00AM
Expires
Fri, January 25th, 2013 - 7:00AM
Forecaster
Graham Predeger
Avalanche risk The Bottom Line

Fresh wind slabs above tree line coupled with our deep slab potential will keep the avalanche danger at MODERATE today.   Below tree line the avalanche danger is trending toward LOW as we see temperatures and the rain/ snow line descend throughout the day.

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Thu, January 24th, 2013
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
  • Wind Slabs
    Wind Slabs
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at Avalanche.org

Snowfall and winds above tree line were not exceptionally impressive yesterday and overnight but consistent enough to build tender, shallow wind slabs throughout the day.  Snow falling at ridge top locations was dense, though easily transportable by the moderate southeasterly winds.  Expect wind slabs to form on north and west aspects above tree line where small human triggered avalanches will be possible today.  Below the rain/ snow line where wind slabs have not formed there is a generally low avalanche danger.  Yesterday that level was about 1700’ in the Turnagain pass area.  We should see that dropping to around 1000’ today.

Cornice fall-

Cornices are growing quite large in the forecast area with one natural failure noted on Magnum last week that resulted in an avalanche.  The moderate winds and dense snow will continue to add weight and mass to these backcountry bombs.  It is wise to recognize cornices and give them a wide berth when travelling through the mountains.

Avalanche Problem 2
  • Deep Persistent Slabs
    Deep Persistent Slabs
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
More info at Avalanche.org

As we continue to add weight to our snowpack we cannot forget about the deep slab issue we are dealing with this winter.  It’s unlikely a person will trigger a deep slab avalanche today however; either of the previous mentioned issues (wind slabs and cornice fall) can act as the catalyst to affect deeper weak layers resulting in a cataclysmic deep slap avalanche.

Weather
Thu, January 24th, 2013

Below about 1800′ we have continued to lose depth in our snowpack due to warm temperatures and precipitation falling mostly as rain the past several days.   Overnight, temperatures have begun a downward slide and we will see our rain/ snow line descend back to sea level by Friday evening.

Today we can expect 1-2 € of new snow with winds shifting from east to southwesterly, calming by this evening.   For the weekend, temperatures appear to be more of what we come to expect for January in Alaska in the 10 €“ 20 degree range.

_____________________________________________________

Fitz will issue the next advisory tomorrow morning, January 25th.

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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.