Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Fri, April 1st, 2016 - 7:00AM
Expires
Sat, April 2nd, 2016 - 7:00AM
Forecaster
Aleph Johnston-Bloom
The Bottom Line

The avalanche danger is MODERATE  today due to above freezing temperatures, rain and an active glide avalanche cycle. Human triggered wet loose avalanches are possible in steep mid-elevation terrain (1000′-2500′). Triggering a fresh wind slab or cornice fall is possible in the Alpine.  Avoid being under the runout of glide cracks.

Summer use trails with avalanche terrain above should be avoided due to the threat of natural avalanche activity from above. Byron trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood remains  CLOSED for the winter.

*If you are headed to the Summit Lake area don’t forget to check  Summit Lake Summary.  

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Fri, April 1st, 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
  • Wet Loose
    Wet Loose
Wet Loose
Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
More info at Avalanche.org

Record high temperatures were seen around the state yesterday and advisory area saw the warmest temperatures of the season to date.

Sunburst, 3800′: 41F 

Seattle Ridge, 2400′: 44F

Center Ridge, 1880′: 57F

Summit Lake 1400′: 57F

Alyeska mid mountain, 1700′: 48F

Clear skies on Tuesday night that allowed for a surface freeze and winds throughout the day helped keep the natural wet loose activity to minimum despite the warm air temperatures. The building daytime cloud cover across the region also added to the variability of surface warming. In sunny areas there was obvious free water in the snowpack as the day heated up. Last night cloudy skies and rain falling (Center Ridge Snotel recorded an inch of water) will keep the mid-elevation snowpack prime for human triggered wet loose activity on steep slopes. Watch for ski and snowmachine penetration and get off slopes if you are sinking in. Remember once wet snow gets moving it often entrains more snow quickly and can be hard to escape. Yesterday there was a report of skier triggered wet loose avalanche in the Summit area on Butch mountain on a west aspect in the afternoon.

Turnagain Pass from the Center Ridge parking lot. Note the surface reflecting in the sun and the large glide crack on the N face of Cornbiscuit.

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

No glide avalanches were reported yesterday on the warmest day we have had this season. What???……. April Fools! Of course there were glide avalanches reported and observed yesterday. A number of new glide avalanches were observed on Seattle Ridge, in Summit Lake and the Girdwood Valley. We are now trying to track areas to see if glides are releasing in spots without pre-existing cracks. If this is the case steering clear of steep terrain in the mid-elevation band around (not just below) glide cracks may also be advised. Visibility may be limited today and make it harder to see where you are in terrain. We can’t stress this message enough: Avoid being under the runout of glide cracks. Avoid being under the runout of glide cracks. Avoid being under the runout of glide cracks. 

Glide avalanche on Seattle Ridge that released sometime between 9 am and 1 pm.

 I am going to include Heather’s photo from Wednesday again. I think the glide avalanche hazard on the Seattle Ridge up-track is particularly dangerous. 

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

Cornices remain extremely large and perched along many ridgelines.  We haven’t seen an active day of widespread cornice failure yet this season.  This just means they continue to grow and creep closer to failure. New snow and wind as well as the warming temperatures this week could act as a catalysts for cornices to fall.  These features deserve extra space and can break farther back than expected. Keep a wide berth both on ridges and when moving below corniced terrain.

Wind slabs: An inch of water was recorded at the Center Ridge Snotel overnight. This could translate to 5-10″ of snow above 3000′ in the Alpine at Turnagain Pass. This combined with sustained easterly winds may have formed tender wind slabs on along ridgelines. Watch for cracking in the snow and pay attention to how well the snow is bonding to the surfaces below. 

 

Weather
Fri, April 1st, 2016

Yesterday was a mixture of sun and clouds across the advisory area. The region saw very warm temperatures with highs in the 50Fs @ 1000′ and in the 40Fs @ 3000′. Winds blew 20-30 mph from the east with gusts into the 50s. Skies clouded up overnight and there were rain showers with the precipitation favoring Turnagain Pass.

Today will be mostly cloudy with continued rain showers and easterly winds 20-35 mph. Temperatures will be in the mid 30Fs to mid 40Fs.

This overall pattern of showers and cloudy skies will persist through the weekend. There is slightly cooler air moving over the forecast area but temperatures will still be above normal.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 45    0 1.1 121  
Summit Lake (1400′)  43  0 0   41  
Alyeska Mid (1700′)  42  0  .1 107  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 39   ENE   26   54  
Seattle Ridge (2400′) 41   SE    26 54  
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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
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Summit Lake
Closed
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