Turnagain Pass RSS

ARCHIVED - Forecasts expire after 24 hours.
Thu, December 31st, 2015 - 7:00AM
Fri, January 1st, 2016 - 7:00AM
Heather Thamm
Avalanche risk The Bottom Line

Multiple avalanche problems exist in the snowpack at different elevations bands today.

A CONSIDERABLE avalanche danger exists both at Treeline and in the Alpine where windslabs 1-4′ will be likely triggered on steep wind loaded features. Today natural activity is not expected in Turnagain Pass, however due to continued stormy conditions and recent rapid loading triggering a deeper more dangerous avalanche will have very high consequences. Therefore today’s travel advice in the Alpine will adhere to the HIGH danger rating where travel is not recommended.

A MODERATE avalanche danger exists below 1500′ where the snowpack is wet and saturated and a larger avalanche from above could easily run into this elevation band.  

*In the Girdwood Valley where more precipitation was recorded overnight natural activity in this area is more likely. Should winds increase beyond the forecasted 20-30mph range today, avalanche danger will be HIGH in the Alpine.

Special Announcements

Recent high winds and new snow have created a variety of instabilities both within and outside of our forecast zone. Yesterday a very lucky skier triggered a windslab on Peak 3 in the Anchorage Front Range and fortunately was not caught. Click HERE for pictures and description of the incident. Until stormy conditions subside, avalanche danger will remain elevated in the Southcentral region.

FCNFAIC is now accepting applications for TWO NEW scholarships! Both scholarships are for avalanche education up to $500. One will be awarded to a snowmachiner and the other to a skier or non-motorized user.

 Please include in your application: name, mailing address, your financial need and how you plan to spread avalanche awareness to your community post-award.   Applications due by 10PM on January 6th.   Please send  your applications to  chugachavyfriends@gmail.com

The Friends-CNFAIC board  looks forward to hearing from you!

Thu, December 31st, 2015
Above 2,500'
3 - Considerable
Avalanche risk
3 - Considerable
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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

Stormy weather has been the theme of our holiday break with over 4.5’ of new snow recorded at Center Ridge Weather Station. On December 29th and December 30th two separate storms brought a mix of rain and snow and high sustained ridgetop winds averaging over 70mph with gusts well over 100mph for multiple hours. Rain/snow line pushed as high as 1800’ saturating the snowpack at the Treeline elevation band. As observed yesterday this rapid loading event has created a variety of avalanche problems that will be challenging to manage today.

1) Wind slab: Triggering a wind slab 1-4’ is likely on steep wind loaded features where multiple layers of wind affected snow exist. Yesterday these wind loaded areas were easy to spot due to their pillow-like shape, but today another 4-5” of snow is expected and moderate Easterly winds 20-30 mph will be transporting more new snow on top, thus adding additional stress to an already stressed out snowpack.

2) Persistent slab: If slides break into older weak layers, we could see very large avalanches, up to 6′ thick (more on this below).

3) Cornices: With such strong winds and warm snow at ridgetops, we can expect cornices to be tender. These ‘backcountry bombs’ are likely to trigger a wind slab or step down to a deeper instability. Avoid ridgelines with large cornices and don’t put yourself below one.

4) Wet loose avalanches: Rain on snow has saturated to upper layers of the snowpack below 1500’. This is more of a concern in areas with terrain traps and in steep channeled terrain where an avalanche from above will be impossible to escape. 


Avalanche Problem 2
  • 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

On the Southern side of Turnagain Pass and extending into the periphery of zone of Summit Lake, this concern is elevated, where a generally thinner snow pack exists. Triggering an older weak layer will be more likely in these areas and possible in Turnagain Pass and Girdwood.  

Some of the avalanches triggered by avalanche hazard reduction by the Alaska Railroad and ADOT ran on older layers, and several large natural D3 avalanche were reported over the last two days including one on Butch Peak in Summit Lake and another at Lower Russian Lake, outside of the forecast zone.

A lot of uncertainty exists as to how easily a person could trigger one of these deeper instabilities. Recent high winds have moved a lot of snow around creating more potential for thinner areas in the snowpack and more stress on the thicker areas. These thin spots will be likely trigger points where a person could unknowingly collapse a weak layer below.  Also a larger trigger like a snowmachine or a cornice failure could be just enough force to tip the balance in deeper areas of the snowpack. Obvious signs of instability like ‘Woomphing’ are unlikely to be present or serve as a warning.

Right now the snow pack is stressed out! It is not the time to get into steep terrain even if a brief window of visibility opens up. The only way to manage this avalanche problem is to avoid steep terrain including being in the runout zone of a steeper slope above. Should you choose to venture into the higher elevation band today cautious routefinding and conservative decision-making are essential. 

This avalanche came down on December 28th and picture was sent to us from the public yesterday. Heads up if you are travelling to Barber Cabin. This is the second time this path has slid in the last month.

Thu, December 31st, 2015

The last five days has brought 5.4 € ­ ­ ­ ­of snow water equivalent to Center Ridge Weather Station. This has been in the form of mostly snow, but warm temperatures above freezing level reached just above this elevation band on several occasion in the last 3 days. Strong storm force winds averaged in the 70’s mph with multiple gusts reaching 117mph early morning on December 30th. Rain/snow line reached just over 1800′.

Yesterday a brief break in the weather was observed in Turnagain Pass; skies cleared temporarily allowing for a period of cooling on the snow surface. Below 1000′ temperatures stayed above freezing and scattered rain showers persisted all day in Girdwood and Portage Valley. Ridgetop winds decreased into the 20 mph range between 11am €“ midnight.

Overnight showery conditions persisted thoughout the whole forecast zone. Easterly ridgetop winds increased into the 30-40 mph. Rain/snow line remained around 1500′.

Today scattered showers will continue with up to another .5 € of water expected today. This will be in the form of rain below 1500′ and up to 5 inches of snow in the upper elevations. Winds are expected to be moderate from the East, 20-30mph at ridgetops. Expect more scattered showers and above freezing temperatures into the weekend.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 32F   4   .8   73  
Summit Lake (1400′) 34F    1 .3   19  
Alyeska Mid (1700′) 33F   3   1.66   53  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 25F   ENE   32   72  
Seattle Ridge (2400′) 28F   n/a    n/a   n/a    
Recent Observations for Turnagain Pass
Date Region Location
05/13/24 Turnagain Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South
05/13/24 Turnagain Observation: Turnagain Pass non-motorized side
05/12/24 Turnagain Observation: Warm up Bowl
05/07/24 Turnagain Observation: Turnagain Pass Wet Slabs
04/29/24 Turnagain Avalanche: Turnagain aerial obs
04/27/24 Turnagain Observation: Johnson Pass
04/23/24 Turnagain Observation: Turnagain Sunny Side
04/21/24 Turnagain Observation: Bertha Creek
04/20/24 Turnagain Avalanche: Spokane Creek
04/16/24 Turnagain Observation: Cornbiscuit
Riding Areas

The riding areas page has moved. Please click here & update your bookmarks.

Subscribe to Turnagain Pass
Avalanche Forecast by Email

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.