Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, February 7th, 2016 - 7:00AM
Expires
Mon, February 8th, 2016 - 7:00AM
Forecaster
Aleph Johnston-Bloom
The Bottom Line

A MODERATE  avalanche hazard exists throughout the advisory area. Human triggered avalanches are possible. Signs are pointing to a stabilizing snowpack but there is still the need for elevated caution as it adjusts to the load of the recent storm.  Evaluate snow and terrain carefully and identify features of concern. Please use safe travel protocols, especially one rider on a slope at a time. Avoid travel on or under cornices and steer clear of glide cracks.  

***Elevated caution is also advised in the Summit Lake area. Please see  yesterday’s  Summit Lake Summary  for more information.  

Thanks to our sponsors!
Sun, February 7th, 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
  • 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

The recent storm deposited up to 3′ of snow in the Alpine and had sustained winds in the 30-40s. There is evidence throughout the terrain of cross and top-loading. It is possible to trigger an wind slab in steep leeward terrain. Look for cracking, listen for hollow sounds and avoid stiff, pillowed snow. In addition, there is a lot of snow available for transport if the winds pick up at all today. There were a few small human triggered wind slab avalanches observed in the Tincan Common Bowl and along CFR ridge yesterday.

Winds and new snow have also added to already large cornices. These are quite hazardous, they often break much farther back than expected and can trigger avalanches on the slopes below. This happened throughout the region last weekend.

 

 Yesterday a snowmachine triggered a cornice fall and took an unexpected dip off the ridge into Warm-up Bowl (-1 Bowl).

Avalanche Problem 2
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at Avalanche.org

We are continuing to investigate how the recent storm has bonded to the old snow surfaces, especially areas that may harbor persistent weak layers and rain crusts. Last weekend there was a large snowmachine triggered avalanche in Groundhog Creek, in the Johnson Pass region, that ran on buried surface hoar. We do not have recent information from that area and that layer may still be reactive. 

This last storm also may have buried a newer layer of surface hoar formed last weekend and/or faceted snow resting on the 1/27 rain crust. These layers were reactive during the storm but we did not observe human triggered avalanche activity on these layers yesterday or have concerning stability test results. Observers were reporting good bonding at the old snow/new snow interface and to the 1/27 rain crust. However, we are not ruling out the possibility of triggering an avalanche on a persistent weak layer today. Look and listen for whumpfing, collapsing and cracking, these are snowpack red flags that indicate unstable snow. Avoid thin spots, steep convexities and rocky areas. These are all possible trigger points in the terrain. This type of avalanche problem may be triggered by the 1st person on the slope or the 15th. It is important to not overload slopes with multiple riders all at once.

Additional Concern
  • 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

Glide cracks still litter the terrain in the Treeline elevation:1000′ – 2500′. New glide cracks continue to appear. Travel underneath should be avoided. They are totally unpredictable, regularly releasing and producing glide avalanches that would be unsurvivable. Yesterday a high mark was observed on Seattle Ridge directly underneath one. Scope out the terrain you want to travel in to avoid this type of exposure. 

 

 

Photo: glide crack on Petes South

Weather
Sun, February 7th, 2016

Yesterday started out cloudy and there was a burst of precipitation in the morning. 2-4″ of new snow fell in a few hours. There was afternoon clearing with partly cloudy skies and sunshine. Temperatures were in the 20Fs at upper elevations and in the 30Fs at the road level. NE winds were light throughout the day and overnight.  

Today will be partly sunny with increasing clouds in the afternoon and a chance of snow showers. Winds will be Easterly 10-25 mph and temperatures will be in the mid-20Fs to mid 30Fs.

Tonight and into tomorrow will be cloudy and snowy again as the next storm moves into the area. 3-7″ of snow is forecasted to fall overnight. Rain and snow showers will continue to be the pattern for the next few days.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 27    4  .5 111  
Summit Lake (1400′) 27    0  0  31
Alyeska Mid (1700′) 30   2   .15    86

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 21    ENE  16  42
Seattle Ridge (2400′) 24 n/a   n/a   n/a  
Observations
Recent Observations for Turnagain Pass
Date Region Location
12/10/19 Turnagain Avalanche: Tincan and Sunburst from the air
12/10/19 Turnagain Observation: Tincan
12/08/19 Turnagain Avalanche: Tincan
12/06/19 Turnagain Avalanche: Sunburst
12/04/19 Turnagain Observation: Sunburst
12/03/19 Turnagain Observation: Hippy Bowl
12/01/19 Turnagain Observation: Tincan, All elevations
12/01/19 Turnagain Observation: Tincan
11/30/19 Turnagain Observation: Tincan Treeline Plateau/ Common Bowl/ Ridge
11/29/19 Turnagain Observation: Sunburst Ob #2
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.

Subscribe to Turnagain Pass
Avalanche Forecast by Email