Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Thu, March 14th, 2013 - 7:00AM
Expires
Fri, March 15th, 2013 - 7:00AM
Forecaster
Graham Predeger
Avalanche risk The Bottom Line

The avalanche danger will start out low and trend toward MODERATE at all elevations as increased snowfall and easterly winds move through the Turnagain Pass area today.   Fresh wind slabs, small storm snow avalanches and potential cornice fall will all be possible today, though should prove manageable with good terrain choices.

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Thu, March 14th, 2013
Alpine
Above 2,500'
Moderate (2)
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
Moderate (2)
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

In the last 48 hours we have seen some big lines skied between Girdwood and Turnagain Pass; it’ll be a good idea to approach big terrain with extra caution today until you can answer the question: How well is todays new storm snow and fresh wind slabs bonding with yesterdays snow surface?  Forecasters found the gamut of surface conditions yesterday from impenetrable crusts at lower elevations to stiff wind board and soft wind textured powder growing surface hoar and facets at upper elevations.  Lots of quick hasty snowpits (hand pits or pole pits) to look at the storm interface may give you good information today before committing to a specific slope. 

Wind slabs forming yesterday and today are expected to be shallow in the 6-18” range proving manageable in most terrain, however pockets still exist where deeper, large avalanches are possible in isolated areas (see photo below).  As always, escape routes and zones of safety are critical when recreating in these mountains.

 

6-8’ hard slab likely ran on a buried crust sometime between March 8th and March 11th. Debris was 10-15’ deep at the toe of this avalanche.  This is a good example of a large, unmanageable avalanche that can be found in isolated areas. Notice how low on the slope the crown face is; likely due to 100+ mph winds last Thursday loading this slope well below the ridgeline.

Avalanche Problem 2
  • Cornice
    Cornice
Cornice
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
More info at Avalanche.org

Cornice fall is still very much on our radar and will be a genuine concern again today.  The good news with cornices is that they are generally easy to manage.  The fact that we can see them means we can avoid them, and avoidance is key.  Don’t spend excessive time underneath cornices and stay much further back than you think necessary when travelling along a corniced ridge.  Cornice fall is quite unpredictable, but expect them to become more unstable late in the day as temperatures and any direct sunlight warm the snow surface.

If you haven’t read Wendy’s write up on the large cornice fall and subsequent avalanche in the Goldpan area, take a few minutes and check it out here.

Weather
Thu, March 14th, 2013

Three days in a row of sunshine and blue sky in the backcountry produced a lot of smiles in the parking lots for those of us lucky enough to find a day off mid-week. Today we can expect moderate winds from the east in the 20-35mph range and mostly obscured skies as a weak surface low moves through our area.   Snow is expected throughout the day in the eastern Turnagain Arm region with totals in the 4-8 € range.   Temperatures look to stay cool enough that snow is expected at sea level.

We may squeeze another inch or two of snow out tonight as this low dissipates and skies begin clearing again overnight and into tomorrow.


Fitz will issue the next advisory Friday morning, March 15th.

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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.