Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Fri, February 15th, 2013 - 7:00AM
Expires
Sat, February 16th, 2013 - 7:00AM
Forecaster
John Fitzgerald
Avalanche risk The Bottom Line

The avalanche hazard is CONSIDERABLE above treeline where over a foot of new snow and winds have created dangerous slabs that will be easily triggered today.   Below treeline the hazard is MODERATE, where isolated pockets of wind slab and storm snow will be possible for skiers and snowmachines to trigger.

Special Announcements

AK DOT will be conducting avalanche hazard reduction work today on the Seward Highway between 9:15AM and 11:00AM between Girdwood and Portage (MP88-83). Motorists should expect delays up to 45 minutes. Updates can be found at 511.alaska.gov.

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Stop by the motorized lot this morning at 11AM! Join CNFAIC forecasters and Gold Level sponsor Alaska Mining and Diving Supply (local Ski-Doo dealer) for an avalanche awareness event and memorial snowmachine ride on the 5th anniversary of this fatal avalanche in Turnagain pass.
http://www.cnfaic.org/accidents/avy021508.htm

Thanks to our sponsors!
Fri, February 15th, 2013
Alpine
Above 2,500'
Considerable (3)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
Moderate (2)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Considerable (3)
Treeline
1,000'-2,500'
Avalanche risk
Moderate (2)
Below Treeline
Below 1,000'
Avalanche risk
Moderate (2)
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

Intense snowfall combined with strong winds in the early part of the day yesterday have created new slabs 2-3′ in depth.  Expect these slabs to be sensitive to the weight of a person or snowmachine today.  While some time has allowed the underlying snow to adjust to this new load, there is enough new snow, especially in wind loaded terrain to warrant concern.  These slabs are large enough on their own to injure or bury a person.  At the mid elevations, there is the possibility of these slabs to step down to older layers of weak snow.  Be on the lookout for shooting cracks, collapsing/whoompfing and snow that has a hollow feel to it.  Staying off of steep rollovers, starting zones and snow that has a rounded or pillowy look will help in avoiding this problem today. 

Avalanche Problem 2
  • Storm Slabs
    Storm Slabs
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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 amounts ranged from a few inches at lower elevations to 16″ in the higher elevations in the past 24 hours.  Expect these slabs to gradually become less reactive as the day progresses.  These instabilities tend to heal quickly.  However, an additional 4 inches of snow today will keep this problem lingering through the day.  Expect storm snow to release in terrain over 35 degrees as we experienced yesterday.  This problem will be more apparent and pronounced as you gain in elevation, particularly where new snow amounts exceed 10″.

 

 

 

Additional Concerns
Persistent Slabs

A crust that formed in the latter part of January has shown up as a problem in certain areas in our region in the past week.  A thin layer of weak snow between this crust and 2-3 feet of snow is the interface that concerns us most.  This crust is most pronounced between 1,800-2,400′.  This problem is not as geographically widespread as our primary concerns.  When traveling within this elevation band today steer away from slopes over 35 degrees, as avalanches in the new snow have the potential to step down to these older layers of weak snow.  

Cornices

Cornices have significantly gained in mass over the last 24 hours.  Keep your distance from cornices today.  They will likely be sensitive to the weight of a person or snowmachine.

Weather
Fri, February 15th, 2013

The mountains around Turnagain Arm have picked up 16″ inches of snow with 1″ of water in the higher elevations over the past 24 hours.   Winds averaged 30mph out of the East in the morning yesterday and temps were moderate, averaging in the low 20s at 3,800′.   Snowfall was most intense during the late morning/early afternoon yesterday.

Lingering snow showers are continuing to put down light amounts of snow around the area.   Winds calmed down in the afternoon yesterday and are currently averaging 2mph out of the West at the Sunburst weather station.   Temps are currently 20 degrees F at ridgetops and around 32 F at sea level.

Today lingering snow showers should produce up to 2-4 inches of accumulation.   Ridgetop winds will blow out of the West at 5-20mph and temperatures at 1,000 feet will be in the high 20s.

Tomorrow we should see clearing skies as a small ridge between low pressure systems moves through the area.

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Wendy will issue the next advisory tomorrow morning, February 16th.

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Riding Areas
Updated Thu, June 01st, 2023

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
Closed May 15.
Placer River
Closed
Closed May 15.
Skookum Drainage
Closed
Will close to motorized use on April 1, 2023 per the National Forest Plan.
Turnagain Pass
Closed
Will close on June 1.
Twentymile
Closed
Scheduled closure May 1.
Seward District
Carter Lake
Closed
Scheduled closure May 1.
Lost Lake Trail
Closed
Scheduled closure May 1.
Primrose Trail
Closed
Scheduled closure May 1.
Resurrection Pass Trail
Closed
Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor
Closed
Extended opening until May 15.
South Fork Snow River Corridor
Closed
Scheduled closure May 1.
Summit Lake
Closed
Scheduled closure May 1.

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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.