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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, February 14th, 2016 - 7:00AM
Expires
Mon, February 15th, 2016 - 7:00AM
Forecaster
Wendy Wagner
The Bottom Line

There is a MODERATE avalanche danger in the mountains surrounding Turnagain Pass for a variety of avalanche problems. First, glide avalanches, that release on their own, are possible at the Treeline elevation band (1,000-2,500). Second, human triggered wet loose avalanches will be possible at this same Treeline band. Third, Wind slab avalanches, up to 2′ thick, and cornice falls are possible in the Alpine (above 2,500′) where it has been lightly snowing and blowing.

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Sun, February 14th, 2016
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
No Rating (0)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Moderate (2)
Treeline
1,000'-2,500'
Avalanche risk
Moderate (2)
Below Treeline
Below 1,000'
Avalanche risk
No Rating (0)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • 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

Although there are many human triggered avalanche concerns out there, glide avalanches remain the primary concern due to their destructive nature. This season is turning out to be a season where mapping glide cracks and limiting/avoiding time under them is just part of the game. The most recent glide we know of that has released at Turnagain Pass was 3-4 days ago on the Eddies ridge

Photo: Glide avalanche on Eddies, released sometime late 2/10-early 2/11.

Avalanche Problem 2
  • Wind Slabs
    Wind Slabs
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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

While many folks are waiting for the skies to clear and temperatures to cool off before venturing into the mountains, it has been snowing a bit and blowing quite a bit over the past several days in the Alpine – above 2,500′. Specifically, between 1 and 2 feet of new snow has fallen over the past 3 days with winds in the 20-25mph range on the ridgetops from the East. Due to lack of travel and visibility in these areas we don’t have first hand data as to how the wind driven snow is bonding, if cornices are falling and the like. However, we know from past experience that this warm snow is quite sticky and stabilizes relatively quickly. This will most likely be the case for today and into the week. Nonetheless, things to watch for at the upper elevations:

Wind Slabs:  Steep slopes that have been, or are currently being, loaded with wind deposited snow are suspect for triggered a wind slab avalanche. These could be 1-2′ or more thick. Watching for cracking in the new snow and jumping on small terrain features and test slopes can be good ways to see how well slabs are bonding. 

Cornice Falls: GIVE CORNICES a wide berth!! these are likely to be tender with the warm temperatures and could be deadly if you were to take a fall off a ridgeline with one. Also, similar to glide avalanches, limit time spend under cornices.

*Shallow snowpack zones: South of Turnagain Pass and the Summit Lake area. These areas have old weak layers in the snowpack that, if loaded with enough snow/wind, could produce a large avalanche. This is something to keep in mind if you are headed to these zones this week with the expected clear skies.

Additional Concern
  • 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

It will be another moist day out there. Temperatures dipped to 32F at 1,000′ overnight and it is lightly snowing at the Pass this morning, but temperatures are forecast to climb up again today. Rain up to 1,500′ is possible and we have .2-.4″ of it with 2-4″ of snow in the Alpine. The snow at the mid-elevations is wet and saturated. These are prime conditions for triggering a wet loose avalanche on steep slopes. To initiate a wet loose slide the slope has to be quite steep, but once it starts moving can gain a lot of momentum and run to valley bottoms. Steering clear of steep slopes with ‘boot-top’ wet snow is an avalanche forecaster’s rule of thumb.

Weather
Sun, February 14th, 2016

Partly cloudy skies with some blue holes covered the region yesterday. Light precipitation fell, adding ~.2″ of rain below 1,000′, and was mostly centered around Turnagain Arm. Around 2″ of snow has fallen in the past 24-hours above 1,500′. Temperatures dropped to 32F at 1,000′ and are holding steady in the mid 20’s on the ridgelines. Winds have been sustained in the moderate range with averages 20-25mph from the East along the ridgetops.  

For today, we are expecting mostly cloudy skies along with light precipitation. Between .2-.4″ of rain is expected to fall below 1,500 with 2-4″ of wet snow above this. The rain/snow line is currently around 800′ this morning but looking to climb a bit through the day. Ridgetop winds are expected to remain moderate from the East, 20-25mph. Temperatures remain warm, mid 30’s F at 1,000′ and mid 20’s F at 3,500′.

For Monday we remain in this unsettled warm and showery pattern, but for Tuesday we could see cooler temperatures and a real break in weather.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′)  32 3    0.3 104  
Summit Lake (1400′) 34   0    0 30  
Alyeska Mid (1700′) 33   1.5    0.15 84  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 24   NE   22   54  
Seattle Ridge (2400′) 27   –   –   –  
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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.

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