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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Friday, January 8th 2016
Created: Jan 8th 4:02 am
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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
 Show the Complete North American Avalanche Danger Scale
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Special Announcement

Tommorrow CNFAIC forecasters are hosting a FREE Avalanche Rescue Workshop from 11:00am to 12:30pm at the motorized lot on Turnagain Pass. This is a great opportunity to practice beacon searches, learn strategic shoveling techniques and meet local forecasters! This workshop is open to everyone and anyone (motorized and non-motorized), novices and experts. We hope to see you there!

Filing for the PFD this week? Remember, The Friends of the CNFAIC is part of PICK.CLICK.GIVE. Your donations are greatly appreciated and an integral part to making the CNFAIC possible and sustainable. 


The Bottom Line

Today the avalanche danger is MODERATE both at Treeline and in the Alpine. Triggering a wind slab is possible today in steep leeward terrain. Be aware of large cornice features and recent glide crack movement and avoid putting yourself on or under these unpredictable hazards. Pay attention to changing conditions as the next storm effects the region.

Below 1000’ the avalanche danger is LOW where triggering an avalanche is unlikely.

*Outside of our forecast zone in Summit Lake where a generally thinner snowpack exists triggering a persistant slab 3’ thick is a concern. Cautious route-finding and careful snowpack evaluation is advised. Check out the observations page. The Summit Summary will be updated tomorrow.


Primary Concern

Triggering a wind slab today in steep leeward terrain is possible today. Winds over the past few days have deposited additional snow, continuing to cross load and top load terrain features. Look for pillowed snow, listen for hollow sounds and pay attention to stiff snow under your skis, snowboards or snowmachines. Investigate if the stiff snow is overlaying soft snow. Watch for shooting cracks and remember even a small pocket of wind slab in steep terrain can have high consequences. Wind slabs are notorious for letting you travel out onto them and then breaking above you. Evaluate carefully before committing to steep terrain from above or below.

****In some parts of the advisory area 5-7' of settled and wind effected storm snow is sitting on a layer of old faceted snow on top of the Thanksgiving Rain Crust. This still needs to be a consideration as you travel into the backcountry today. This Deep Slab concern is a low probability, very high consequence set-up.  As always it is important to use safe travel practices: ride slopes one at a time, have an escape route planned, regroup and/or park in safe areas and watch your travel partners. Do not overload slopes with multiple skiers, boarders or snowmachines. 

Wind transporting snow on Turnagain Pass. 

 


Secondary Concern

Very large cornice features have formed throughout the region as a result of a two-week storm that deposited ~9’ of snow and was accompanied by very high winds. Cornices have the potential to fall naturally or be triggered by the weight of a person or machine and can be very dangerous. Travel under or on them should be avoided. They have the tendency to break farther back from the ridge than expected and can trigger an avalanche on the slope below by adding a lot of weight quickly. As you approach ridgelines and the entrances to backcountry bowls make sure you aren't accidently traveling on overhanging snow. A snowmachine took a dip into the cornice crack near the top of the Seattle Creek uptrack.

A large crack was found on the Magnum ridge above the cornice.


Additional Concern

Glide cracks are continuing to appear throughout Turnagain Pass. They may lead to Glide Avalanches which are incredibly difficult to predict and will be deep and destructive if they do release. Travel under glide cracks should be avoided. In addition the cracks can be quite deep and falling into one could be very hazardous. They are sometimes mistaken for old avalanche crowns. The characteristic "brown frown" shape can help you identify the glide cracks in the terrain. 

 

 

Glide cracks on Seattle Ridge just north of the common uptrack. 


Mountain Weather

Yesterday was mostly overcast. There were a few breaks in the clouds alternating with periods of very light rain/snow showers. Temps were in the 30Fs at 1000' and in the 20Fs at 3000'. Winds were mostly light from the ENE with a few gusts in the 30s. 

Today will be mostly cloudy with light rain and snow showers, 0-2" of snow. Snow line is forecasted to be around 1800'. Easterly winds will increase throughout the day into tonight as the storm moves into the region. Precipitation is forecasted to be heavier tonight into tomorrow morning. Snow line may increase to 2000'.

This showery pattern will persist through the weekend as the plume of warm moist air is pushed into the area by the low in the Gulf.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 31  0  81
Summit Lake (1400') 30 0  26
Alyeska Mid (1700') 32 0 58 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 23  ENE  15  38 
Seattle Ridge(2400') 25 n/a  n/a  n/a 

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 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
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
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
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