Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Wed, February 27th, 2019 - 7:00AM
Expires
Thu, February 28th, 2019 - 7:00AM
Forecaster
Wendy Wagner
The Bottom Line

A generally  LOW  avalanche danger exists across all elevations bands for the Turnagain area. Steep rocky southerly facing slopes may heat up enough by the afternoon for a person to initiate wet sluffs.  Give cornices a wide berth and avoid travel under glide cracks.  Good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are, as always, key ways to minimize risk.  

SUMMIT LAKE / SILVERTIP / JOHNSON PASS:  *** We want to emphasize the difference here.  More caution is advised  South of Turnagain Pass.***  Keep in mind a thin snowpack with buried old weak layers exist. There is more potential for triggering a large slab avalanche in this zone. Choose terrain wisely. Please read the Additional Concerns below.  

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Wed, February 27th, 2019
Alpine
Above 2,500'
Low (1)
Avalanche risk
Treeline
1,000'-2,500'
Low (1)
Avalanche risk
Below Treeline
Below 1,000'
Low (1)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Low (1)
Treeline
1,000'-2,500'
Avalanche risk
Low (1)
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
  • Normal Caution
    Normal Caution
Normal Caution
Normal Caution means triggering an avalanche is unlikely but not impossible.
More info at Avalanche.org

The Turnagain, Girdwood and Placer zones have entered the “Normal Caution” regime of backcountry hazards. What this means is triggering an avalanche is unlikely but not impossibleWhat to keep in mind in the backcountry today:

  • Wet sluffs on steep south facing slopes – watch for snow on steep south facing slopes to become wet and punchy by the afternoon. In this case, triggering a wet sluff will be possible if the slope is steep enough. Most southerly slopes have already gone through several melt-freeze cycles and natural wet loose activity is not expected today. 
  • Outlier slab avalanches – It’s unlikely but not out of the question that person could trigger an old wind slab in steep terrain, all aspects – shaded or sunny.
  • Cornice falls – Cornices that are baking in the sunshine can become weaker and more unstable. We need to continue giving these a wide margin. 
  • Glide avalanches – It’s always best to limit exposure under glide cracks. Please let us know if you see a glide crack release into an avalanche. The last known glide avalanche was on Goat Mt. in the Girdwood Valley 8 days ago. 

Today will be the 6th day of sunny and springtime weather; sunglasses have entered back into the morning checklist. The warmest day so far was Monday 2/25. Several wet loose avalanches were seen on steep rocky slopes. A few slabs popped out on Monday as well under rock bands triggered by wet loose debris. These slabs, seen in the photo below, were likely composed of the 10-16″ of settled storm snow from 2/16-2/20. Today is not expected to be as warm as Monday but tomorrow has a chance. Keep close tabs on how the snow surface is heating up during the day. It is springtime and time to consider travel routes for late in the day. 

 

Steep rocky southerly facing slopes are feeling the springtime sun and warm ambient air temperatures. Many wet loose avalanches released Monday afternoon 2/25 during the warmest day seen this season (this one pictured is from Crow Ck drainage).

Additional Concern
  • 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

South of Turnagain – Summit Lake/Silvertip/Johnson Pass zones:  A shallow snowpack with a generally poor snowpack structure exists in these areas. A variety of weak layers sit in the mid and base of the snowpack and were re-activated last Thursday by the outflow wind event. Many natural avalanches were seen on windloaded slopes in the Summit Lake area. Although whumpfing has been observed in the Summit area, no signs of instability may be encountered before a slab is triggered. 

Again a quick recap of the weak layers sitting in the pack:

  • Valentine’s Layer:  Small facets, 10″-16″ deep, last avalanches on 2/21 due to wind event region-wide. Not showing signs of reactivity in Turnagain/Girdwood/Placer currently. Layer was responsible for the 2/19 snowboarder remotely triggered slab on Seattle Ridge.
  • MLK Jr Layer:  Buried surface hoar, 2-3′ deep, last avalanches seen in this layer 2/21 in the Summit Lake region. All natural slides.
  • Basal facets (large faceted snow near the ground): This layer has only been found in the Summit Lake region and produced at least one very large natural avalanche on Thursday, 2/21.

If you’re headed this way, remember the snowpack becomes more complex – evaluate terrain exposure and the snowpack as you travel. 

Natural avalanche on Fresno Pk from last Thursday, 2/21. This slide was triggered by significant wind loading from the outflow wind event. It broke in weak layers deeper in the snowpack. 

Weather
Wed, February 27th, 2019

Yesterday:   Sunny skies with light and variable ridgetop winds were once again over the region. Daytime temperatures warmed to the mid 30’sF from valley bottoms to the high peaks. Overnight, the nocturnal inversion set back in and single digit temperatures are being reported at Portage and in low-lying areas along the Seward highway such as Johnson Pass.  

Today:   Sunny skies will again be over the region. Winds are expected to be a bit more organized along ridgetops and blowing light 5-10mph from the NW. Temperatures should warm to the mid 30’sF by the early afternoon in the lower elevations while the upper elevations will remain in the low 30’sF.  

Tomorrow:   Sunny skies and light winds are on tap tomorrow. However, we could see a few degrees warmer daytime temperatures at all elevations according to the weather models. The ridge of high pressure over Southcentral AK will keep the skies mostly clear through the week.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 25   0   0   60  
Summit Lake (1400′) 16   0 0   29  
Alyeska Mid (1700′) 24   0   0   56  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 30   E   4   12  
Seattle Ridge (2400′) 29   N   2   5  
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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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