Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, March 31st, 2019 - 7:00AM
Expires
Mon, April 1st, 2019 - 7:00AM
Forecaster
Wendy Wagner
The Bottom Line

VERY WARM temperatures will increase the avalanche danger from LOW this morning  to CONSIDERABLE  by this afternoon/evening. Large and dangerous wet loose, wet slab and glide avalanches may release naturally once the sun softens surface crusts and weakens the snowpack. All slopes above 1,000′ facing East, South and West that see direct sunshine should be carefully evaluated before traveling.  Watch and avoid being under glide cracks! Cornices are breaking off in the heat of the day – give them an extra wide berth.  

PORTAGE VALLEY:   Summer trails with avalanche terrain overhead, such as Byron Glacier Trail and Crow Pass, are not recommended in the afternoon or evening due to the possibility of an avalanche occurring above.  

SUMMIT LAKE (& INTERIOR EASTERN KENAI MTS):   Human triggered slab avalanches remain possible in upper elevation terrain on all aspects. This area has a thin  snowpack with many weak layers. High elevation sun-affected slopes are the most suspect for triggering a slab.  

SEWARD/LOST LAKE:   The snowpack is warming up and dangerous avalanche conditions are occurring late in the day in this area as well. A  large avalanche released on Mt. Marathon Thursday.  

Thanks to our sponsors!
Sun, March 31st, 2019
Alpine
Above 2,500'
Considerable (3)
Avalanche risk
Treeline
1,000'-2,500'
Considerable (3)
Avalanche risk
Below Treeline
Below 1,000'
Moderate (2)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Considerable (3)
Treeline
1,000'-2,500'
Avalanche risk
Considerable (3)
Below Treeline
Below 1,000'
Avalanche risk
Moderate (2)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Wet Loose
    Wet Loose
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    Size
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.

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

Although the days have been warm lately, today will be hot! As of 6am this morning air temperature along ridgelines are several degrees warmer than previous mornings and sit in the 30’sF. Direct sunshine and light winds could push afternoon temperatures into the 40’sF and even 50F in the mid and upper elevations. The snowpack has already seen many days of a springtime melt-freeze pattern, yet today our hackles should be up for unusual avalanches in the afternoon and evening. Not only are the mid-elevations expected to see wet avalanches, we could see wet avalanche activity on sunny slopes in the high alpine. Wet loose avalanches will be the most likely, but wet/moist slabs are possible.  

Yesterday we know of two new avalanches. One was a glide/full depth avalanche at 5:30pm on Seattle Ridge’s Repeat Offender slide path. This piled 8-10 feet of debris on to the common motorized up-track. See the photos and video below. The other was a glide on Lipps SW face that reported to have released around 11:30am.

Things we can do for a safe day in the mountains is plan ahead. Know the terrain you are traveling and if it will be affected by the sun. The boot test is a great way to assess how the daytime warming is, or is not, affecting the surface. If your boot easily sinks into mushy wet snow, it’s time to get onto shaded slopes or off the one you are on and well away from any runouts. Wet loose avalanches can start small from a person pushing soft wet snow as they ski or ride. If the terrain is large enough, this small slide can turn into a large and unmanageable avalanche. Wet avalanches can send debris far and to places we may not expect.

CORNICES: Cornices are very large and direct sunshine will destabilize them. A cornice fall has the potential to trigger an avalanche on the slope below and could break farther back than expected. 

 

 

Glide/full depth avalanche just above the common motorized up-track on the Repeat Offender slide path. Debris covered the up-track with 8-10′ of debris. 

Looking at avalanche and debris from the up-track.

 

Cornices are peeling off and a significant danger to people getting pulled off a ridge. Getting washed over by cornice triggered avalanche from below is also a hazard.

 

Avalanche Problem 2
  • Glide Avalanches
    Glide Avalanches
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    Size
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.

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

Glide cracks are popping and avalanching daily. If any time is good to simply avoid traveling under glide cracks, now is the time. A large crack was reported to have released on Lipps SW face yesterday and the Seattle Ridge full depth avalanche is likely a glide that did not have a crack present before releasing; making our current avalanche situation more unpredictable. Remember, glides can release even if a hard surface crust is present (unlike the wet loose and wet slab avalanche problems). Many cracks are opening up in popular terrain and keep an eye out for them. 

With so many old glide avalanches scarring the mountainsides, how do we know if any are new? This is good information as new glide releases tell us they are ‘active’ and more can be expected.  

Additional Concern
  • Deep Persistent Slabs
    Deep Persistent Slabs
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
More info at Avalanche.org

South of Turnagain in Summit Lake and areas in the interior Kenai Peninsula have a very poor snow structure with variety of old weak layers in the mid pack (facets and buried surface hoar.) Triggering a persistent slab 2-3’ deep as slopes warm in the afternoon sun is possible at the upper elevations. The avalanche seen on Butch Mtn. in Summit Lake last week is a good reminder that sunny hot days can surprise us! Keep in mind deeper weak layers could be lurking in these areas and sunlit slopes are the most suspect.

Weather
Sun, March 31st, 2019

Yesterday:   Sunny skies with light ridgetop winds were over the region. Temperatures reached 40F at 2,500′ and 32F at 4,000′. Overnight a warmer air mass has moved in maintaining these warm upper elevation temperatures. Valley bottoms have cooled slightly and sit in the upper 20’sF.  

Today:   Very WARM air with sunny skies are forecast. Ridgetop winds should be light and variable. Temperatures may reach 50F at 2,500′ with direct sunshine and up to 40F at 4,000′.  

Tomorrow:   Sunny skies will prevail as the ridge of high pressure over us remains entrenched. Temperatures tomorrow look to remain warm, yet slightly cooler air may stream in for Tues/Wed. Clouds and a chance for precip is still on the horizon for Thur/Fri, but models are trending at keeping this to our South and we may see sunny skies for the work week.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 38   0    0  68
Summit Lake (1400′) 37   0 0   61  
Alyeska Mid (1700′) 37   0   0   22  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 29    variable 5   19  
Seattle Ridge (2400′) 35   variable   3   6  
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