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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Fri, February 26th, 2016 - 7:00AM
Expires
Sat, February 27th, 2016 - 7:00AM
Forecaster
Aleph Johnston-Bloom
The Bottom Line

The avalanche danger in the Treeline and Alpine elevation bands is CONSIDERABLE today. This means human triggered avalanches are likely on slopes 30 degrees and steeper and natural avalanches are still possible. Cornices are huge, glide cracks are releasing and wet snow is a concern. Elevated caution is recommended. Very cautious route finding and conservative decision-making are important if venturing into the mountains today. Watch for changing conditions this afternoon as the next storm intensifies.  

The danger is  MODERATE  below 1,000′ where debris from an avalanche above may run into channeled terrain.

Dangerous avalanche conditions also exist in  the Summit Lake area. See Saturday’s  Summit Lake Summary  and click  HERE  for recent observations from the last few days.

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Fri, February 26th, 2016
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
  • 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

After a brief period of clearing yesterday the clouds rolled back in and light snow and rain fell overnight. Today is forecasted to be cloudy with rain and snow showers and the wind and precipitation is forecasted to pick up tonight. What this means is there is a bit of a lull in major loading of the snowpack but there is still a lot of uncertainty about the set-up. We have received a lot of snow and rain (in a short period of time) and had strong winds. Warm temperatures have increased the likelihood that the storm layers are bonding but this has increased the chances for wet avalanches (see below). We have very limited information on the snowpack in the Alpine. There are a variety of concerns for today. This all means a conservative mindset is important. 

Storm Slabs: Fluctuating temperatures and snowfall may combine to create storm slabs as new layers of snow are deposited. Pay attention to how well the new snow bonds to the snow below. 

Wind Slabs: Winds today will continue to add stress to very large wind slabs in leeward terrain. Human triggering of these could be very dangerous due to the depth of slab. Avoid steep wind-loaded slopes. 

Cornices: Natural cornice fall activity is still possible today and could trigger an avalanche on the slope below. Again this something you want to avoid traveling on or underneath. Cornices will be tender and could break way farther back than expected. Falling down the slope with a refrigerator to school bus sized chunk of snow on your snowmachine or skis would be terrible, if not deadly.

Avalanche Problem 2
  • Wet Loose
    Wet Loose
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.
More info at Avalanche.org

The storm that ended yesterday brought rain up to almost 1800′ that fell on to 1-2′ of snow. Temperatures remain around freezing or above at lower elevations. Rain is forecasted to fall again today up to 1600′.  All this has created a set-up that is prime for wet avalanches. Natural wet loose and wet slab avalanches will be possible in the mid elevation band today and human triggered avalanches are likely in steep terrain. Look for roller ball activity, that is an indication that the surface snow is loosing strength and avoid terrain traps. Wet snow can be very hazardous especially if it gets moving and stuffs you into bad spot.

 

Recent wet slab avalanche South of the Bertha Creek campground.

 

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

Well… another glide avalanche happened! It was easy to check it out while getting gas at the Girdwood Tesoro. This is a great reminder that many glide cracks are still lurking under the new snow and have the potential to release at any time. Glides threaten a lot of well-traveled terrain on both the motorized and non-motorized side of the highway. Observers also reported that some of glide cracks are reappearing that indicates they are on the move. Avoid travel below glide cracks or under terrain where they might be.

 

Glide avalanche on the West face of Pyramid Peak. This happened sometime before 10:30 am when we first received a report of it.

Weather
Fri, February 26th, 2016

The intense storm moved out yesterday and there was a brief window of clearing before the clouds and precipitation moved in again bringing rain and snow showers. Temperatures were above freezing for most day at lower elevations and in the mid to high 20Fs above 3000′. Easterly winds were moderate 25-35 mph with some gusts in the 50s.  

Today will be mostly cloudy with continued rain and snow showers. Rain/snow line is forecasted to be around 1600′. 0-5″ of snow could fall at higher elevations. Winds will Easterly 20-40 mph. Temperatures will be in the 30Fs and 40Fs. Precipitation and winds will pick up overnight.  

This pattern continues into the weekend with warm temperatures, rain and snow and Easterly winds. Southcentral is in a ‘warm southeast flow’. Lows continue to move into the Gulf and moisture will continue to push into the advisory area.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′)  34 0   .6   134  
Summit Lake (1400′)  35 0 0   42  
Alyeska Mid (1700′)  33 1 .14   104  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 25   ENE   25   67  
Seattle Ridge (2400′) 27    n/a n/a   n/a  
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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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