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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Monday, December 12th 2016
Created: Dec 12th 4:52 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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
Special Announcement

Mark your calendar for this week's Fireside Chat: Avalanche Awareness and Rescue w/CNFAIC in Girdwood at the Powder Hound Ski Shop! December 15 @ 6:30 pm - 8:00 pm. FREE.  

The Friends of the CNFAIC is offering two $500 avalanche education scholarships through the Rob Hammel fund. One is for avalanche professionals and the other is open to anyone!  The deadline for both scholarships is Dec 15th! For more information click this link HERE

Thanks to everyone who took time out of their beautiful sunny weekend to collect observations and submit them! We really appreciate the information!


The Bottom Line

A generally LOW avalanche danger exists across all elevations bands for the Turnagain Pass zone. Triggering a 1-2' avalanche is unlikely but not impossible. The most suspect slopes are in steep terrain at the high elevations where someone just might be able to break off an old wind slab or find a slope with the buried surface hoar that hasn't slid. Good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are key ways to minimize risk. Ease onto steep slopes and be prepared to change your plans if an area becomes too crowded.

There is snow to sea level, just enough to put a LOW danger rating on the Below Treeline Elevation band. If venturing into the 'periphery' forecast zones, such as Girdwood Valley, more caution is advised due to limited information about the snowpack in these areas. This should also be part of the equation if you are heading to ice climb in Portage where even a small slide could have high consequences.

If headed to Summit Lake check out the Saturday Summit Lake Summary HERE


Primary Concern

Over the weekend many people were out in the mountains slope testing and there were no human triggered avalanches reported. With a stable weather pattern dominating our region and very little changes affecting the snowpack we are in a Normal Caution phase for avalanche issues. These include:

1- Triggering an outlier avalanche. This would most likely be an 'unsupported slab' that sits above a cliff or steep rocky terrain. More on this below in ‘Additional Concerns.’

2- Triggering an old wind slab - Avoid hard stiff snow sitting in steep rocky terrain where a small isolated wind slab could have high consequences.  

3- Triggering a cornice fall. Cornices are small right now, but similar to wind slabs they could take you down somewhere you don't want to go. Give cornices a wide berth.

4- Sluffs on steep slopes. Small sluffs were observed yesterday, and as the surface snow becomes weaker under clear skies the potential for bigger stuff will increase. 

Remember LOW hazard doesn't mean NO hazard! Look for signs of instability and use good travel techniques.

Final ridge up Pastoral, near 4400' Photo: Andy Moderow


Additional Concern

Even with LOW avalanche danger it is still important to remember the weak layer 1-2' below the surface i.e. the notorious Nov 16th buried surface hoar. Although we have not seen an avalanche release in this layer since December 3rd and the slab character has been changing due to the cold temperatures, there are still slopes away from the 'popular' zones that have yet to be tested. These are the areas most suspect. Triggering is unlikely but not impossible! 

 


Mountain Weather

Yesterday was cold, clear and calm. An inversion kept ridge top temps in the teens to low 20Fs and lower elevations in the single digits or below zero. This was true overnight as well. 

Today and tomorrow will be similar with clear skies, light N-NW winds and temperatures ranging from single digits in the valleys to teens and low 20Fs at higher elevations.

According to the NWS "the rather stagnant weather pattern will be changing dramatically" later in the week. Precipitation and warmer temperatures are forecasted. Stay tuned!  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 14   0 20 
Summit Lake (1400')  3 0  0
Alyeska Mid (1700')  17  0  9

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  20  W  5  16
Seattle Ridge(2400')  21  variable  3  10

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: Mar 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
Skookum Drainage: OpenSKOOKUM DRAINAGE CLOSES TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

Subscribe to the Turnagain Area Avalanche Advisory:

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
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