Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Wed, January 27th, 2016 - 7:00AM
Expires
Thu, January 28th, 2016 - 7:00AM
Forecaster
Aleph Johnston-Bloom
The Bottom Line

As rain, wind and snow impact the Turnagain Pass and surrounding areas today we will have a  CONSIDERABLE  avalanche danger at all elevations above 1,000′. Human triggered storm and wind slab avalanches will be likely on slopes 35 degrees and steeper. Natural avalanches will be possible. Cautious route finding and conservative decision-making are advised as the storm continues through the day.

Yesterday was an active day for glide avalanches. Avoid traveling in areas where glide cracks threaten from above.  

The avalanche danger is MODERATE below 1000′ where debris running into channelized terrain from above is possible.

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Wed, January 27th, 2016
Alpine
Above 2,500'
Considerable (3)
Avalanche risk
Treeline
1,000'-2,500'
Considerable (3)
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
Considerable (3)
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
  • 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

After a brief break in the stormy weather yesterday, that gave backcountry travelers an opportunity to get out in the sunshine, we are back in it today with a warm, wet and windy storm rolling through. Overnight there has been .5 of water, roughly 5-8″ of snow. Today we are expecting another .5″-1″ of precipitation; this equates to rain below approximately 1,500′ and 5-10″ of snow above. The winds have been blowing 30-40 mph from the ENE with gusts up into the 70s actively loading leeward terrain.

In the Alpine, above 2,500′, where dry snow is falling avalanche issues are expected to be confined to what we call ‘storm snow instabilities’. This means avalanches will be composed of the new storm snow and are not expected to break into layers deeper in the pack. The question will be how well the new snow bonds to the old snow. The most likely avalanches will be on wind loaded slopes where fresh wind slabs 5-20″ thick have formed. These are always the most ‘touchy’ during formation or just after. Avoid travel on or under steep leeward terrain. Smooth rounded surfaces, hollow feeling snow, stiff snow over soft snow and shooting cracks intiated traveling on foot or machine, are all signs of wind loading and something to steer clear of on steep slopes today. 

In the 1000′-2500′ elevation band pay attention rain on snow and to how well the new snow is bonding to the old rain crust/snow surface, expect wind slabs especially in cross loaded areas like Seattle Ridge. The rain/wet snow combination may create the conditions for wet loose avalanches in this elevation band. 

*Cornice falls will again be a concern today with the warm temperatures, new snow and wind loading. These can break naturally at anytime as well as under the weight of a person. They can trigger an avalanche below and be very dangerous. 

Note: The Girdwood Valley recieved about twice as much water (.9″) as Turnagain pass Sunday and additional load last night. If venturing into the upper elevations around Girdwood, fresh wind slabs and storm slabs are likely to be thicker.  

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

Several recent glide avalanches were observed yesterday. Glide cracks are continuing to open and grow. These are dangerous and unpredictable. As with cornices, these are best dealt with through avoidance and limiting any exposure underneath them. Poor visibility today will make it harder to locate the exisiting glide cracks in the terrain.

 

 

 

Glide avalanche on Seattle Ridge. We believe this released in the early morning yesterday.

 

Weather
Wed, January 27th, 2016

Yesterday, cloudy skies in the morning gave way to mostly clear and sunny weather in the afternoon. Temperatures were in the mid-20Fs above 3000′ and low 30Fs around 1000′. Winds from the ENE were in the teens throughout most of the day and then picked up to 30-40 mph range overnight. Gusts reached into the 70s this morning. .5″ of precipitation (5” of snow above 1500′)  fell overnight.

Today skies will be cloudy with a mixture of snow and rain as the storm continues. Precipitation is forecasted to be heavy at times. Up to an 1″ of water (5-10″ of snow) is possible. Temperatures will be in the high 20Fs to mid 30Fs. North to  East winds, 25 to 30 mph decreasing in the afternoon. Additional rain/snow showers are expected overnight.  

This stormy pattern continues through the week as a low in the Gulf and associated strong frontal system effect the region.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 30    3 .5   92  
Summit Lake (1400′)  29  0 0   29
Alyeska Mid (1700′)  33  2.5 .25   73

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′)  23  ENE  25 74  
Seattle Ridge (2400′)  26 n/a   n/a   n/a  
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Riding Areas
Updated Wed, December 11th, 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
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South Fork Snow River Corridor
Closed
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Summit Lake
Closed
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