Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Tue, January 26th, 2016 - 7:00AM
Expires
Wed, January 27th, 2016 - 7:00AM
Forecaster
Graham Predeger
The Bottom Line

There is a MODERATE avalanche danger today above 1,000′ in the mountains surrounding Turnagain pass.   Fresh wind slabs 6-12 € thick will be possible to trigger in steep terrain on leeward (wind-loaded) sides of ridges in the alpine.   In the treeline elevation band (1,000 €“ 2,500′) an overabundance of glide cracks are keeping the danger pegged at MODERATE as these may release spontaneously and without warning.

Below treeline the danger is LOW as unfortunately, we lack snow to have much of an avalanche problem.

Take a look at the Summit Lake snow and avalanche Summary as well as recent observations from the Summit Lake zone if your plans have you skiing further South of Turnagain pass today.

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Tue, January 26th, 2016
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
Low (1)
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
Low (1)
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

Surface instabilities in the form of fresh wind slabs make up the primary avalanche concern today.  With more wind than precipitation yesterday in the Turnagain pass area we can expect to find wind slabs in the 6-12” range on wind-loaded and cross-loaded slopes above treeline.  As these last couple of storms have come in quite warm, wind slabs appear to be adhering well and may be stubborn to initiate.  Very steep, wind-loaded terrain may be the exception.  Overall, across the Turnagain pass zone (and above about 2K), the snowpack is deep and is lacking any reactive persistent weak layers.  Aside from glide cracks (more info below) any instability today should be relegated to the top 12-18” of our snowpack.  You can quickly test for surface instability by conducting hasty hand pits or jumping on (no consequence) test slopes with your skis or machine. 

Cornices deserve a note as well, as these warm, windy storms prove ideal to continue to add to their mass.  Avoid time spent below and when travelling along a corniced ridge, whether on skis or snowmachine maintain a healthy distance (and then some!) from the edge.  

Note: The Girdwood Valley recieved about twice as much water (.9″) as Turnagain pass yesterday.  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

Visibility yesterday limited a look at many of the glide cracks that we’ve been monitoring over the last 2-weeks, including a behemoth on the SW face of Corn Biscuit.  If someone were to tangle with a glide avalanche, it would simply be a ‘wrong place at the wrong time’ scenario.  It’ll be best to limit or avoid altogether time spent underneath glide cracks and recognize them for the dangerous, unpredictable avalanche problem that they are.

This photo is of a very large glide crack as observed last Thursday, 1/21.  Yesterday, visibility was too poor to see if this had progressed anymore toward failure but see Wendy’s obervation from 1/24.  She was able to see visible changes in this crack over an hour timespan.  

 

Another concern today in this mid-elevation band comes in the form of wet-loose avalanches as the snowpack is quite heavy and wet below 2,000′.  With continued warmer than normal temps and a slight chance of a few rays of sun today, we may see some wet-loose and/ or roller ball activity in steep, mid-elevation terrain.  

Weather
Tue, January 26th, 2016

A low ceiling and steady precipitation around eastern Turnagain arm dominated yesterday’s weather. Temps were hovering around 34 F at 1,000′ (37 F at sea level) with a rain/ snow mix at the Turnagain pass parking lots and the rain-snow line around 1,300′.   Ridgetop winds were moderate from the NE averaging in the 30’s and gusting to 63 mph before tapering off a bit overnight.   Center ridge SNOTEL site (1880′) picked up a couple inches of snow (.4 € water) in the last 24 hours while Girdwood picked up .9″ of water as reported at the Alyeska mid-station.  

Today looks to be a slight break in our active weather pattern before another Low and associated front rolls through southcentral AK tomorrow morning.   Temperatures are expected to be in the mid-30’s at 1,000′ with ridgetop winds from the East in the 10-25mph range.   Skies will be mostly cloudy but we shouldn’t expect to see more than an inch or two of snow wrung out today in favored areas of the Pass.    

More unsettled weather is on tap as we head toward the weekend with the big quetion being precipitation type and just where that rain/ snow line will fall.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 32    2 .4   92  
Summit Lake (1400′) 33    1 .2   28  
Alyeska Mid (1700′)  33  0 .9   73  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′)  26 ENE   28   63  
Seattle Ridge (2400′)  28 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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