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Avalanche Advisory

Turnagain Area Avalanche Advisory
Tuesday, April 2nd 2019 7:00 am by Aleph Johnston-Bloom
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

Warm temperatures and direct sunlight will increase the avalanche danger from LOW this morning to MODERATE by this afternoon/evening. Human triggered wet loose avalanches on steep, solar aspects, especially above 3000', are possible once the sun softens surface crusts and weakens the snowpack. Avoid being under glide cracks and give cornices an extra wide berth! 

PORTAGE VALLEY:  Summer trails with avalanche terrain overhead, such as Byron Glacier Trail and Crow Pass, are still not recommended in the afternoon or evening due to the possibility of an avalanche occurring above. 

SUMMIT LAKE (& INTERIOR EASTERN KENAI MTS):  Human triggered slab avalanches remain possible in upper elevation terrain on all aspects. This area has a thin snowpack with many weak layers. High elevation sun-affected slopes are the most suspect for triggering a slab. 

SEWARD/LOST LAKE:  Similar to the Turnagain Area travel on solar aspects should be carefully evaluated later in the day and travel under glide cracks should be avoided. 


 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

Wet Loose

Almost Certain
Very Likely
Likely
Possible
Unlikely

Chance

Historic
Very Large
Large
Small

Size

Yesterday was slightly cooler than the day before and overnight temperatures were cooler than the past couple nights. Clear skies promoted a solid freeze overnight.  The snowpack has already seen many days of a springtime melt-freeze pattern in the low and mid-elevations. Overall the possibility of natural wet loose and wet slab avalanches has decreased. However, there is still the potential for person, on skis or a machine, to trigger an avalanche in the afternoon/evening on solar aspects as the crust breaks down and slopes get soft and punchy. This is heightened in the Alpine where the warming of the surface snow is more recent. 

A safe day in the mountains includes planning ahead. Know the terrain you are traveling on and under and if it will be affected by the sun. The avalanche danger on steep slopes on the southern end of the compass will increase this afternoon/evening. Play the aspects for the best conditions and to stay safe. The boot test is a great way to assess how the daytime warming is, or is not, affecting the surface. If your boot easily sinks into mushy wet snow, it's time to get onto shaded slopes or off the one you are on. Wet loose avalanches can start small from a person pushing soft wet snow as they ski or ride. If the terrain is large enough, this small slide can entrain snow and turn into a large and unmanageable avalanche. 

CORNICES: Cornices are very large and direct sunshine will destabilize them. A cornice fall still has the potential to trigger an avalanche on the slope below and could break farther back than expected. 

Snowmachine triggered wet loose avalanche on to the uptrack on Friday, 3-29-19. Photo: Sean Fallon

 Cornice over Warm up bowl, 3-30-19. Photo: Graham Predeger. Give cornices a wide berth. 


Avalanche Problem 2

Glide Avalanches

Almost Certain
Very Likely
Likely
Possible
Unlikely

Chance

Historic
Very Large
Large
Small

Size

Glide cracks are appearing throughout the advisory area and have been avalanching daily. Yesterday was the first day without notable activity reported but the message remains the same. Avoid traveling under glide cracks at all times of the day!  Remember, glides can release even if a hard surface crust is present (unlike the wet loose and wet slab avalanche problems). Many cracks are opening up in popular terrain and keep an eye out for them.  Glide avalanches are full depth avalanches that have the potential to very dangerous. 

Glide avalanche South side of Wolverine, observed 3-30-19.

Glide avalanche Lynx creek, witnessed in motion on 3-29-19.


Mountain Weather

Yesterday: Sunshine and clear skies with temperatures in the high 30Fs to mid 40Fs. Winds were light and westerly. Overnight temperatures dipped into the 20Fs and mid to low 30Fs. Skies were clear and winds increased slightly overnight gusting into the teens. 

Today: More sunshine and clear skies with temperatures in the 30Fs in the Alpine and 40Fs at lower elevations. Winds will be westerly 5-10 with gusts into the teens. Overnight skies will be partly cloudy and temperatures are forecast to decrease into Wednesday as cooler air moves over the region. 

Tomorrow: Clear and sunny again with cooler temperatures and light winds. There is still some uncertainty about the precipitation potential on Thursday and Friday but expect clouds and a chance of rain/snow showers.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 39  66 
Summit Lake (1400') 34   0    0   22 
Alyeska Mid (1700')  40   59 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 32   3  13
Seattle Ridge(2400')  37    W    1  4

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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