Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, March 24th, 2019 - 7:00AM
Expires
Mon, March 25th, 2019 - 7:00AM
Forecaster
Wendy Wagner
The Bottom Line

A  HIGH  avalanche danger remains over the region. Warm and wet weather continues to melt down the snowpack and cause large wet slab and wet loose avalanches to release naturally. These avalanches are occurring on slopes near and below 3,000′. They are gouging to the ground, running to valley bottoms at times and very destructive. Above 3,000′ storm snow avalanches and cornice falls are likely.  Once again, travel in avalanche terrain is NOT recommended.  

PORTAGE VALLEY:  Very large avalanches continue to release naturally. Avoid summer hiking trails that travel through avalanche paths, such as Crow Pass, Byron Glacier and Johnson Pass Trail.

SUMMIT LAKE (& INTERIOR EASTERN KENAI MTS):   Despite less precipitation, natural and human triggered avalanches remain likely. The snowpack has many weak layers are currently being overloaded and stressed by warm temperatures and rain.  

SEWARD/LOST LAKE:  Similar to Turnagain – the hazard remains elevated as many wet slab avalanches continue to release.  Travel in avalanche terrain is not recommended.

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Sun, March 24th, 2019
Alpine
Above 2,500'
High (4)
Avalanche risk
Treeline
1,000'-2,500'
High (4)
Avalanche risk
Below Treeline
Below 1,000'
High (4)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
High (4)
Treeline
1,000'-2,500'
Avalanche risk
High (4)
Below Treeline
Below 1,000'
Avalanche risk
High (4)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Wet Slab
    Wet Slab
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    Size
Wet Slab
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.

Likelihood of Avalanches
This graphic depicts how likely you are to trigger avalanches or encounter natural avalanches while traveling on avalanche prone slopes. Unlikely means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. The chance of triggering or observing avalanches increases as we move up the scale. Certain means that humans will be able to trigger avalanches on many slopes, and natural avalanches should be expected.

Size of Avalanches
This graphic depicts the potential size and destructive force of expected avalanches. Small avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become large enough to bury, injure, or kill people, large enough to bury or destroy vehicles and break a few trees, and large enough to destroy railway cars, buildings, or a substantial amount of forest. Historic avalanches are massive events capable of destroying villages and gouging or altering the landscape.
More info at Avalanche.org

One last cloudy and rainy day before skies finally clear and let the sun in. Today marks the 18th, and hopefully last, day of this impressive warm March storm series. Despite few folks in the backcountry and limited visibility yesterday, we know of six natural wet avalanches that occurred at Turnagain Pass. One was a wet slab just under Tincan’s CFR ridge, photo below. Another was a glide avalanche on SW facing Eddies Ridge and four were seen/heard by an Alaska Avalanche School Level 1 course. Of these four, three were seen on North facing Sunburst Ridge and one on SE facing Seattle Ridge. During the past 24-hours, close to an inch of rain fell in Girdwood Valley, 2.8″ in Portage Valley and almost half an inch at Turnagain Pass. Today, only .25″ is forecast yet avalanche conditions are expected to remain similar as even light rain on snow up to 2,000′ will keep the pack unstable.

A few things to consider for backcountry travel:

  • Know, and avoid, avalanche terrain. Give runout zones an extra wide berth. These wet avalanches can do wild things and run where we may not expect them to.
  • Glide cracks are opening and some are releasing. Limit/avoid being under cracks. New cracks have been seen in the Tincan Trees – photo below.
  • Cornice falls. Cornices are huge and have been growing and falling for two weeks now. Beware once skies clear!
  • Upper elevation storm snow problems. The higher in elevation the drier the snow – wind slabs, sluffs and storm slabs are all a concern. Direct sunlight this week could trigger large slabs in the Alpine. Heads up.
  • Shallow snowpack zones such as Summit Lake harbor many old weak layers (facets and buried surface hoar). Over the past few days numerous large wet slab and dry slab avalanches have released. These zones are just as dangerous, if not more, right now.

Looking ahead: Sunshine and very warm temperatures (even in the upper elevations) are in the forecast beginning Monday for the week. Avalanche danger may stay more elevated than one might expect. It is true once the snowpack begins to freeze it will lock up and limit avalanche activity. HOWEVER, the pack is incredibly wet and it will take more than one clear night to stabilize it for the morning hours. Of course, sunshine and warm ambient temperatures will quickly destabilize the snowpack again during the day/evening hours. Hence, springtime avalanche issues will be in full effect next week! Keep in mind upper elevations could produce some very large avalanches cornice falls during this warm and sunny period. The mountains do weird things in the spring and we need to be extra cautious with route selection, where we eat lunch, avoiding steep southerly slopes late in the day, and on. 

 

Wet slab avalanche releasing yesterday (Mar 23rd) off of Tincan’s CFR ridgeline, Westerly aspect at 2,000′. *Note the opening glide cracks in the trees lower on the slope. 


Wet slabs and wet loose avalanches wreack havoc on Seattle Ridge. Many steeper slopes has avalanched and many are hanging in the balance. 

Thanks to Alex McLain for snapping this photo of a wet slab on the shoulder of Moose Mtn in the Summit Lake area (near the Hope Y). The avalanche occurred sometime between 11am and 1pm yesterday, Mar 23rd. 

Weather
Sun, March 24th, 2019

Yesterday:   Cloudy skies with light to heavy rain were seen below 2,500′ and wet snow above this. Just under an inch of rain was seen the Girdwood Valley and almost half an inch at Turnagain. Portage Valley was clearly favored coming in with 2.8″ of rain during the past 24-hours. Estimated snow totals at the high elevations are 8-10″ upper Girdwood Vally and 3-6″ at Turnagain Pass. Ridgetop winds were easterly in the 15-25mph range. Temperatures have decreased slightly this morning and sit at 35F at 1,000′ and in the upper 20’sF along ridgelines.

Today:   Mostly cloudy skies with light rain showers are expected over the region as one last low-pressure moves through. There is a chance we could see some breaks in cloud cover later in the day. Rain should fall up to 2,000′ with .25″ forecast (2-3″ wet snow at the upper elevations). Ridgetop winds should increase slightly to the 20-30mph range with stronger gusts from the East. Temperatures should stay in the mid-30’sF at 1,000′ and the upper 20’sF along ridgelines.  

Tomorrow:   Beginning Monday a high-pressure ridge will build in for the work week. This will bring clear skies and warm temperatures at all elevations; ridgetops could see 40F. Tuesday the upper elevation temperatures should climb even higher, possibly hitting the mid 40’sF along ridgetops during the peak of the day.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 37   0     0.4   73  
Summit Lake (1400′) 36   0    0.1 25  
Alyeska Mid (1700′) 35   0   0.85   68  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 28   NE   16   47  
Seattle Ridge (2400′) 32   SE   13   32  
Observations
Recent Observations for Turnagain Pass
Date Region Location
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
11/29/19 Turnagain Observation: Sunburst Ob #1
11/27/19 Turnagain Observation: Tincan
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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