Avalanche Advisory

Turnagain Area Avalanche Advisory
Thursday, March 31st 2016 7:00 am by Heather Thamm
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger is CONSIDERABLE today due to above freezing overnight temperatures, and increased warming from the sun today. Glide avalanches and natural wet loose avalanches in steep terrain are possible today. Human triggered wet loose avalanches are likely. Cautious route-finding and terrain evaluation are essential today. Avoid being under the runout of glide cracks.


Summer use trails with avalanche terrain above should be avoided due to the threat of natural avalanche activity from above. Byron trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood remains CLOSED for the winter.

*If you are headed to the Summit Lake area don't forget to check Summit Lake Summary

 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
0 NO RATING Below Treeline / Below 1,000'
Special Announcement

ATTENTION PROCRASTINATORS!!!!  Today is the deadline to file for your 2016 Permanent Fund Dividend --  Remember The Friends of the CNFAIC is part of PICK.CLICK.GIVE. Your donations are greatly appreciated and integral to making the CNFAIC possible and sustainable.  Be part of the 'Movement'! Thank you for your support!

Headed to Arctic Man 2016? Don't forget your beacon, shovel and probe! CNFAIC will be there all week and offering two FREE companion rescue workshops. Click HERE for more information. We hope to see you there!

Avalanche Problem 1

Will daytime temperatures reach a season high today? 

Sunny skies combined with unseasonable warm weather could push temperatures into the high 40F’s to mid 50F’s today.  Last night was the second night in a row of above freezing temperatures in the mid elevation zone and rain/snow line yesterday was observed around 2500’. At treeline 4-6” of wet snow is sitting on a supportable crust where wet loose avalanches will be a concern today on slopes steeper than 35 degrees. The size will be directly proportional to the size of the terrain, and larger slopes will be more dangerous where more snow is available to entrain and pick up momentum. In the alpine where drier snow is sitting on a smooth bed surface there is more potential for moist/wet slab activity. Pay attention for rollerballs and avoid being on or under steep slopes today.  The danger will increase with warming temperatures and solar impact throughout the day.

In Girdwood and Portage Valley where more snow has fallen over the last three days, expect wet loose activity to be larger. Cautious routefinding and a conservative mindset will be the best strategy for travel in the backcountry. 



Avalanche Problem 2

The glide avalanche cycle continues without interruption. Yesterday another handful of new glide releases were identified between Girdwood and Turnagain Pass including a large glide avalanche that stopped just short of the Turnagain Arm bike path on Penguin Ridge.

In Turnagain Pass a glide crack on Seattle Ridge has been growing and is starting to threaten portions of the common uptrack.  A recent glide avalanche in this location, above this glide crack occurred on 3/29 in conjuntion with a storm slab. The debris pile is quite large and runs over well-traveled terrain. This should definitely warrant concern, today’s warm temperatures will only be weakening the snowpack. Glide avalanches are completely unpredictable and could happen at any moment, avoidance is strongly recommended.

Portions of the Seattle Ridge uptrack (in orange) are in the runout of a growing glide crack on Seattle Ridge. 


View of recent glide activity on East face of Seattle Ridge with a large glide crack in the foreground on Tincan SW aspect.

Additional Concern

Cornices remain extremely large and perched along many ridgelines. These features deserve extra space and can break farther back than expected. Triggering a cornice will become more likely later in the day with sun and warming temperatures. 

Wind slabs: In the upper alpine (above 3500’) where temperatures have remained below freezing, wind slabs remain a concern on unsupported slopes and will be more suspect during the heat of the day with warming temperatures. These wind slabs could be extra touchy where they are sitting on a stout melt freeze crust below.

Mountain Weather

Yesterday skies were mostly cloudy and with light scattered showers throughout the region. Ridgetop winds were averaged in the 20's mph from the East. Temperatures ranged in the 30F to mid 40F’s, and remained above freezing overnight in the mid elevation zone.  Temperatures in the alpine were just below freezing yesterday and overnight.

Today skies will be mostly sunny with patches of fog. Daytime ambient air temperatures may reach the 50F’s at sea level and 40F’s in the alpine. Winds are expected to be light to moderate from the East and no new precipitation is expected today.

Tomorrow a front will move through Southcentral Alaska bringing another round of rain showers. Temperatures are expected to remain above freezing in the mid elevations and rain/snow line is expected to be around 3000’. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 39  rain  0.2  123 
Summit Lake (1400') 39  rain  0.1  39 
Alyeska Mid (1700') 36  rain  0.13  108 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 29  ENE  17  54 
Seattle Ridge(2400') 31  SE  31   59

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: Oct 05, 2019 )

Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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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.

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