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Avalanche Advisory

Turnagain Area Avalanche Advisory
Tuesday, April 9th 2019 7:00 am by Wendy Wagner
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger remains MODERATE at all elevations. In the mid-elevations, glide avalanches continue to release sporadically and are creating a dangerous and unpredictable hazard. Limit any travel under glide cracks. Additionally, wet loose sluffs are possible on saturated steep slopes below 2,000'. In the Alpine, watch for areas with new wind-drifted snow where small wind slabs may be triggered on steep shaded slopes. And as always, give cornices a very wide berth.

GIRDWOOD VALLEY:  Between 4-6" of new snow has fallen in the higher elevations of Girdwood Valley. Wind slabs up to 10" thick along with dry/moist sluffs could be found on steeper slopes in the Alpine. 

PORTAGE VALLEY:  Summer trails with avalanche terrain overhead, such as Byron Glacier Trail, are not recommended due to the possibility of an avalanche or cornice fall sending debris over the trail.


 Show the Complete North American Avalanche Danger Scale
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Special Announcement

Avalanche Problem 1

Glide Avalanches

Almost Certain
Very Likely
Likely
Possible
Unlikely

Chance

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Size

Glide avalanches continue to be the most concerning avalanche problem for anyone traveling in avalanche terrain. Glide cracks litter the slopes and could release into an avalanche at anytime. Cracks are predominatly opening at elevations below 3,000' and on E, S and W aspects. They are not triggered by people and are very unpredictable and destructive to anything in their path. The last known glide crack to release into an avalanche was Sunday morning, just south of Turnagain Pass near the Hope Wye cutoff. What we can do is keep our eyes open and limit/avoid traveling under cracks (example photo below). This may take some creative route planning in places, but it could be well worth it if a crack decides to release in your vicinity.

WET LOOSE:  Triggering a wet loose avalanche (sluff) on steep slopes that did not freeze overnight is possible. This will be most likely on slopes below 2,000' that have been soaked by rain and remain wet and unsupportable. 
 

Glide cracks on Tincan under Common Bowl. 


Avalanche Problem 2

Wind Slabs

Almost Certain
Very Likely
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Unlikely

Chance

Historic
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It may be wet and raining down low, but it's still relatively dry up high. Above 2,500', anywhere from 1-6" of new snow fell over the region yesterday (favoring Girdwood) which was added to the 3-6" of new snow from over the weekend. Plug in moderate easterly ridgetop winds and we can expect 4-10" thick wind slab on leeward facing slopes. Shaded aspects will be the most touchy as wind slabs are sitting on weak older snow (facets/buried surface hoar). One of these slabs was found on the North Chutes on Tincan Sunday (photo below). Keep a lookout for wind deposited snow, fresh drifts and watch for cracking around your skis/board or machine. Even a small wind slab can be a problem in steep rocky terrain.

Small, shallow skier triggered wind slab on one of Tincan's north facing chutes on Sunday. (Photo Adam Baxter)

 

CORNICES: Cornices remain very large along some ridgelines in the Alpine. These cornices can break suddenly and pull back onto flat ground above a slope. Give them a wide berth and avoid travel directly below them.

South of Turnagain in Summit Lake and areas in the interior Kenai Peninsula still posses a variety of old weak layers within the snow pack. Be aware of a variety of avalanche conditions ranging from small isolated wind slabs to wet loose. Triggering a persistent slab 2-3' deep is becoming an outlier at this point, but the poor snowpack structure is worth noting if headed to Summit.  

Todd's Bowl and the North facing Chutes of Tincan at Turnagain Pass. Winter remains at these higher elevations. 


Mountain Weather

Yesterday:  Cloudy skies with light rain fell up to 2,000' over the region. Girdwood picked up just under 1/2 an inch of rain, while Turnagain Pass saw around a tenth of an inch in the past 24-hours; this equates to 4-6" of snow above 2,500' and 1-2" respectively. Ridgetop winds have been moderate, averaging 10-20mph with gusts near 40mph from the east. Temperatures climbed to the upper 20'sF at 4,000' and the mid 40'sF at 1,000' before dropping to the mid 20'sF at 4,000' and the mid 30'sF at 1,000'. 

Today:  Mostly cloudy skies, with a few breaks in cloud cover, are in store today as a weak low pressure spins in the Eastern Gulf. A few raindrops may fall up to 2,000' with flurries above this in favored areas. No measureable precipitation is expected. Ridgetop winds should remain moderate from the east in the 10-20mph range with gusts into the 30's at times. Temperatures will be on a slow decline as cooler air moves in and highs near 40F are expected at 1,000', while ridgetops remain in the mid 20'sF. 

Tomorrow:  A brief break between systems should bring partly cloudy skies, mild temperatures and light easterly winds for Wednesday. A powerful front is forecast to hit the region Thursday bringing heavy rain, 4-10" of snow above 2,000' and 50-70mph winds. Stay tuned!

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 37  rain  0.1  63 
Summit Lake (1400') 37   0 19 
Alyeska Mid (1700') 35  0.5  0.42  57 

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  NE  14  39 
Seattle Ridge(2400') 31  SE  11  20 

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).

Winter snowmachine use open/closed status and riding conditions updates

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: May 06, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed as of 4.3.19
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: ClosedClosed as of 5/6. Thanks for a great season all, see you next winter!
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
Seward District
Carter Lake: Closed
Lost Lake Trail: ClosedClosed as of 3.22.19 due to lack of snow
Primrose Trail: ClosedClosed as of 4.3.19 due to lack of snow
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: ClosedClose as of 5.1.2019
South Fork Snow River Corridor: ClosedClosed as of 3.20.19 due to lack of snow.
Summit Lake: Closed

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
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