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 24th, 2016 - 7:00AM
Expires
Fri, March 25th, 2016 - 7:00AM
Forecaster
Heather Thamm
The Bottom Line

The avalanche danger is CONSIDERABLE  at Treeline (below 2500′) in Turnagain Pass where glide avalanche activity has been especially active in the last two days. Due to a wet and saturated snowpack human triggered wet loose avalanches in steep terrain (greater than 35 degrees) are also possible in the mid elevation zone and will be more likely in the afternoon with the influence of solar heating.  Cautious route-finding and terrain evaluation are essential today to avoid being under the runout of glide cracks.

In the Alpine above 2500′ the avalanche danger is MODERATE, where triggering a cornice, wind slab or wet loose avalanche are possible and will increase with daytime temperatures.  

*If you are headed to the Summit Lake area don’t forget to check  Summit Lake Summary  here and an HERE for observation from yesterday.

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Thu, March 24th, 2016
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Considerable (3)
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
Considerable (3)
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
  • 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

We have been talking about glide cracks and glide avalanches for months and the past couple weeks have been notably active. In the past couple days our concern for glide avalanches has become more elevated with a wet saturated snowpack and four nights of above freezing temperatures. New cracks are appearing and releasing, and old large cracks are also releasing without warning. The entire East face of Seattle Ridge is covered including the area of Repeat Offender, which has seen accelerated movement in the last two days. The area near the ‘uptrack’ is getting more cramped, with little wiggle room for safely playing in this area. The idea of parking under or someone getting a machine stuck under a glide crack is a total dice roll. Navigating through the mid-elevation band is getting more and more complex. The only way to mange this hazard is avoidance. 

Yesterday glide activity on Seattle Ridge was impressive and several small lobes released near the uptrack. Click HERE for an observation of glide activity from Yesterday.

 

 

Many new glide avalanches were observed yesterday in Girdwood, Twentymile, and Turnagain Pass, including this one on the SW shoulder of Pete’s South. 

 

Uptrack is on far right side of picture; glide cracks cover and have almost connected the entire lookers left side of Repeat Offender on Seattle Ridge

 

Avalanche Problem 2
  • 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

Yesterday temperatures reached the 50F’s at sea level, and for the fourth night in a row the mid elevation zone remained above freezing. This is not helping our wet and saturated snowpack stabilize very quickly. Wet loose natural activity was observed yesterday on all aspects, and on solar aspects the activity was larger and more notable.

Today triggering a wet loose avalanche will be possible below 2500’ on slopes steeper than 35 degrees. Wet avalanches once initiated can entrain more snow rapidly and are very hard to get out of. They can be particularly hazardous if they push you into a terrain trap and bury you deeply. If your skis or snowmachine are sinking deep into wet snow this is an obvious clue that the snow is unstable. Stick to low angle terrain and avoid runout zones where avalanches from above may catch you. Today’s weather forecast is for scattered rain showers, which could mean periods of sun. If the sun becomes more of a theme than cloud cover, expect natural wet avalanche in the alpine on solar aspects as well.

Wet loose activity observed yesterday morning on the West face of Magnum before the sun and day time temperatures started playing a roll.

 

Additional Concern
  • 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

Wind slabs and Cornices:

Finding a lingering wind slab 1-2’ thick is possible in steeper terrain today and will be more likely to trigger during the heat of the day on solar aspects. Watch for cracking in wind-loaded areas and avoid travel on or under cornices. Today’s warm temperatures will make cornices more likely to fail. 

Weather
Thu, March 24th, 2016

Yesterday daytime temperatures reached a high of 48F at the Center Ridge weather station and a high of 51F at Bird Flats. Ridgetop winds were calm and skies were mostly sunny throughout the day.

Overnight temperatures barely reached freezing (31F) at Seattle Ridge weather station as of 6am. At Center Ridge weather station there was an overnight low of 37F, which has an elevation of 1800′. Ridgetop winds were light from the Northeast and no precipitation was recorded in the last 24 hours.

Mid elevation temperatures will likely reach the mid to high 40F’s and temperatures in the alpine will also be above freezing for most the day. Scattered rain showers will move through the area, but only a trace of precipitation expected. Expect Northeast ridgetop winds to be in the 10-20mph range.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 40   0   0   127  
Summit Lake (1400′) 38   0   0   42  
Alyeska Mid (1700′)  38 0   0   106  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 32   NE   8   15  
Seattle Ridge (2400′) 35   SE   8   12  
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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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