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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Friday, January 22nd 2016
Created: Jan 22nd 4:17 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
Kitchen Legal, LLC
Special Announcement

Saturday, January 23rd, 10:30-12: SheJumps in collaboration with the Alaska Avalanche School & CNFAIC will be putting on a basic avalanche rescue clinic focused on companion rescue. Sorry guys, this is a women's specific clinic and will review efficient search techniques using a beacon, probe and strategic shoveling. This is a great opportunity to get some hands on practice with the help of an instructor. For more details click HERE.

Monday, January 25th, 7-8 pm: Come to the Blue and Gold Board Shop for a FREE Avalanche Awareness class taught by CNFAIC forecaster Heather Thamm. For more details click here: HERE. Know Before You Go!


The Bottom Line

Today a MODERATE avalanche danger exists in the Alpine and at Treeline. Triggering an isolated wind slab is possible on steep wind-loaded features. In places protected from the wind, loose snow avalanches could be fast moving and easily knock you off your feet in steep terrain. In the mid-elevation band (at Treeline), glide cracks pose a significant threat as they continue to grow and release. Avoid travel underneath them.

LOW avalanche danger exists below 1000’ where triggering an avalanche is unlikely.

If you are thinking of going to Summit Lake, be aware that different avalanche problems exist within the snowpack. Click HERE to read the Summit Lake Summary from this last weekend. 


Primary Concern

Wind slabs: Over the last few days several wind events combined with over a foot of new snow have created wind slabs up to 20” thick on leeward features. The good news is this new snow seems to be bonding well with the old snow below, however not enough time has passed for this hazard to have completely healed. Yesterday we received reports of skiers triggering pockets of wind slab on steep wind-loaded slopes. Trigging an isolated wind slab in the wrong place, like over a cliff or above a terrain trap, could have high consequences. As wind slabs get older they get stiffer and may allow for travel out onto them before they release. Watch for shooting cracks and avoid hollow sounding snow.

Cornices: Already large cornices have received additional stress from the new snow load and strong winds earlier in the week. These have a tendency to break farther back than expected and can send you for an undesirable ride.  Approach ridgelines with caution and avoid being on or directly below cornices features. 

Image from FS National Avalanche Center.

 


Secondary Concern

In places protected by the wind 12” of loose unconsolidated snow could be fast moving in steep terrain. Loose snow can easily knock a person off of their feet or take them for a ride over a cliff or into a terrain trap. Manage your ‘sluff’ and avoid terrain features with high consequences. Skiers have reported being surprised by these conditions over the past couple days. 

 


Additional Concern

Today at Treeline (the 1,000’ – 2,500’ elevation band) on all aspects, pay attention to and AVOID glide cracks. These can lead to glide avalanches that are very unpredictable as we have seen over the past few days. Yesterday there was a large release on the South face of Sharks Fin. The cracks on Corn Biscuit were recently observed and continue to grow.  There is no discernable pattern to predict a failure, as they tend to fail naturally and on their own schedule. Warm temperatures can trigger them and so can cooling temperatures. Cracks can form and release in seconds or days later or sometimes a glide crack won’t release at all. The new snow has made it harder to see the existing cracks and glide releases in the terrain. 

It is best to give glide cracks a wide berth.  AVOID spending time underneath and if skiing or riding in terrain with glide cracks, try and map them out before your travels so as not to end up directly on top of or inside one.  Remember, when these do fail, they tend to be destructive, failing to the ground and bringing the entirety of the snowpack with them.

Don't mess with the 'Brown Frown'!!!

 


Mountain Weather

Yesterday was mostly cloudy with light Northeasterly winds. Temperatures were in the mid-20Fs with a warming trend overnight.

Today will be mostly cloudy with a mix of rain and snow showers, 1-3 inches of snow accumulation is possible. Winds will be easterly 10-20 mph. Temperatures will be in the mid-20Fs to mid-30Fs. Snow showers will continue overnight with an additional 2-4 inches of snow forecasted and a slight increase in winds. 

A series of low-pressure systems are lining up to impact the area over the weekend and into next week. The NWS is calling this a 'Parade of Lows'. Expect rain/snow showers and winds to increase as these systems move through. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880')  28 86 
Summit Lake (1400')  28 0 27 
Alyeska Mid (1700')  29 0 67

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  27 ENE  10  25 
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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