Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, March 6th, 2016 - 7:00AM
Expires
Mon, March 7th, 2016 - 7:00AM
Forecaster
Heather Thamm
The Bottom Line

The avalanche danger is  MODERATE  today in Turnagain Pass for loose snow avalanches, wind slabs, glide avalanches and cornice fall. Triggering an isolated wind slab or loose snow avalanche is possible in steep terrain following 6 € of new snow that fell yesterday. Give glide cracks and cornices lots of space as they can release without warning. Evaluate the terrain for any of these issues and pay close attention to how the sun is affecting the surface snow on sunny aspects.

* If you are headed to the Summit Lake area don’t forget to check the  Summit Lake Summary  and click  HERE  for recent Summit Lake observations.

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Sun, March 6th, 2016
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
No Rating (0)
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
No Rating (0)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Dry Loose
    Dry Loose
Dry Loose
Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
More info at Avalanche.org

Welcome to spring! Even yesterday when skies were mostly covered with clouds the sun’s radiation still played a role in heating the surface of the snow. The sun’s warmth combined with already warm daytime temperatures has the potential to add stress to our avalanche concerns: wind slabs, loose snow, and cornice fall. Monitor the surface snow and plan your day accordingly.

Loose Snow: Yesterday’s new snow (5”) was not bonding well with the surface below and was easily triggered on steep test slopes. This new snow was fast moving and released easily from your ski tips. Keep this problem in mind if entering into terrain where falling could have high consequences. This avalanche problem can be managed by letting your ‘sluff’ move past you when descending. On solar aspect in the afternoon wet loose avalanches will be more difficult to manage and harder to escape. Look for natural point releases on steep slopes, near rocks, and consider avoiding aspects where the sun is heating the slope.

Wind Slabs: Yesterday this new snow arrived with moderate winds and just enough time has passed to help form cohesive slabs. It is unknown how well this new snow is bonding with the surface below, thus be on the lookout for wind slabs in the alpine. Pay attention for soft pillow shaped features, shooting cracks and ease into steeper terrain with caution.

Top 5″ of loose snow was easily triggered yesterday on steep test slopes in Turnagain Pass. 

 

 

Avalanche Problem 2
  • Glide Avalanches
    Glide Avalanches
Glide Avalanches
Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.
More info at Avalanche.org

Countless glide cracks continue to threaten large areas of terrain throughout Turnagain Pass, including a mine field of cracks that cover most of the Southwest face of Cornbiscuit. There were several glide cracks that slid on Friday in the Summit Lake area and one possible new glide avalanche in the Lynx creek drainage. Glide cracks have been widening and coming out of hiding after they were covered by wind and snow during the storm cycle that ended a week ago. Limiting time spent under cracks is crucial, as they will spontaneously release without warning.

One of several many large glide cracks along Cornbiscuit’s Southwest face. Photo by Kevin Dee.

 

Additional Concern
  • 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

Very large cornice features can be found along most ridgetops throughout Turnagain Pass. Some have large cracks and remain precariously perched in place.  As is the general rule, give them lots of space, and limit time under them. Today warming temps and sun will be adding more stress and a snowmachine or person too close could tip the balance. 

Some cornice features may have large cracks like this one that overhangs the SW aspecet of Magnum. Photo taken on 3-2-2016

Weather
Sun, March 6th, 2016

Yesterday snow and rain showers left 6 € of new snow in the Turnagain Pass area, 2 € happened before 7am yesterday. By late morning snow turned to rain along the highway and a brief period of sun appearted mid-day. Rain/snow line was around 1400′. Temperatures spiked in the high 30’s F at Center Ridge Weather Station and Easterly ridgetop winds were moderate become light in the afternoon and evening.

Overnight temps remained just above freezing along the road corridor (33F) and skies remained overcast. Winds were light with no new accumulation after midnight.

Today expect isolated rain and snow showers throughout the morning and afternoon becoming partly cloudy by early evening.  Temperatures are expected to reach the mid-high 30’s F by mid-day with sun being an influence with thin cloud cover.

Tomorrow a similar pattern of rain and snow showers will continue to move through Southcentral, Alaska.

Today’s weather forecast for scattered showers can produce a ‘greenhouse effect’ where thin cloud cover can trap short wave radiation from the sun and easily heat up the surface of the snow.  

PRECIPITATION 24-hour data (6am – 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 32   4   0.4   141  
Summit Lake (1400′) 33   1   0.1   44  
Alyeska Mid (1700′) 33   7   0.7   108  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 25   ENE   15   49  
Seattle Ridge (2400′) 27    n/a  n/a      n/a
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Riding Areas
Updated Mon, December 02nd, 2019

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.
Placer River
Closed
Closed.
Skookum Drainage
Closed
Closed.
Turnagain Pass
Closed
Closed.
Twentymile
Closed
Closed.
Seward District
Carter Lake
Closed
Closed.
Lost Lake Trail
Closed
Closed.
Primrose Trail
Closed
Closed.
Resurrection Pass Trail
Closed
Closed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor
Closed
Closed.
South Fork Snow River Corridor
Closed
Closed.
Summit Lake
Closed
Closed.

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