Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, January 30th, 2016 - 7:00AM
Expires
Sun, January 31st, 2016 - 7:00AM
Forecaster
Heather Thamm
The Bottom Line

Today the avalanche danger is MODERATE in the Alpine and at Treeline where a variety of isolated avalanche problems linger. Above 2500′ it will be possible to trigger wind slabs 1-3′ thick on steep unsupported terrain features. In the Treeline elevation zone (1000′-2500′) glide cracks litter all aspects and can release without warning. In addition to avoiding these problems, recognize that today is the first sunny Saturday in many weeks and it will be extra important to be aware of other groups above and below you and practice safe travel protocols.

The avalanche danger is LOW below Treeline where a stout crust has formed with cooling temperatures.

*Elevated Caution is recommended for Summit Lake where less information is known about the snowpack following a warm and windy storm this week. Click HERE to read the most current Summit Lake Summary.  

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Sat, January 30th, 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

Wind Slabs: Evidence of many large avalanches can be seen throughout Turnagain Pass following a two-day storm that brought strong Northeast winds, rain below 2500’ and 2.5’ of new snow in the Alpine. Wind slabs were active mid to late storm (Jan.27-28), but are healing quickly with cooling temperatures. Triggering a wind slab 1-3’ thick is still possible today in steep terrain where the snow is unsupported. Be on the look out for obvious signs of instability like shooting cracks or active wind loading. Be aware that both the Sunburst and Seattle Ridge anemometers are not functioning and current wind data is not available.

Cornices: With recent snow and wind loading, we can expect cornices to be tender. Remember cornices often break farther back than expected and can add a significant load to the slope below when they fall. Avoid travel on or below them. 

Human Factor: Anticipate parking lots to be full and lots of people recreating throughout Turnagain Pass. Actively communicate with other groups and always practice these safe travel rituals to minimize your exposure in avalanche terrain.

  1. Only expose one person at a time on slopes steeper than 35°
  2. Regroup in safe zones away from the runout of a steep slope
  3. Always have an escape zone 

Several crowns were observed in Todd’s Bowl and in the background on Eddies SW face, all likely occurred near the end of the Jan.27-28 storm.

 

A large D3 wet slab occured mid storm on an East aspect of Seattle Ridge, just South of the motorized lot. Cooling temperatures have helped to quickly stablize this avalanche problem.

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

The addition of rain and 2-3’ of new snow has accelerated the glide avalanche problem. Big brown streaks can be seen on many aspects of Turnagain Pass, including Seattle Ridge, Eddies, Wolverine, and Cornbiscuit. This problem is becoming more widespread in steep terrain between 1000’ to 2500’ where many more cracks have opened up and continue to widen. Since glide cracks can spontaneously release at any time, identify and avoid slopes with known cracks. We could see increased activity today with cooling temperatures – which is thought to be a possible trigger following a period of active loading and rain. 

 

Recent glide avalanche on the East face of Seattle Ridge, North of the Motorized uptrack

 

 

This glide avalanched mid storm and is now covered by new snow, but be aware that glide cracks litter the entire East Face of Seattle Ridge.

 

 

Additional Concern
  • 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

With several feet of new snow and cooling temperatures triggering a point release is possible. Typically loose snow avalanches are not big enough to bury a person, but can catch you by surprise in the wrong place. This is an important hazard to manage in steep terrain where falling can have high consequences.

Weather
Sat, January 30th, 2016

Yesterday skies cleared and temperatures cooled throughout the day dropping into the low to mid 20’s F overnight. At this time no wind data is available, but forecasted winds were expected to have been light.

Today skies are expected to be mostly sunny with patches of valley fog in Turnagain Pass and Turnagain Arm. Temperatures will be in the mid 20F to lower low 30’s F. Today’s forecast is calling for Westerly gap winds through Portage Valley, and light Southwest winds in Turnagain Pass.  

Tempertures are expected to drop into the teens tonight and light Southwest winds will transition to Easterly winds by Sunday as clouds start moving back into the region

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 26   1   0.1   95  
Summit Lake (1400′) 26   0   0   28  
Alyeska Mid (1700′) 29   1   0.1   72  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 21   N/A   N/A     N/A    
Seattle Ridge (2400′) 23   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
Closed.
South Fork Snow River Corridor
Closed
Closed.
Summit Lake
Closed
Closed.

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