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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, January 15th 2017
Created: Jan 15th 5:06 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
The Hoarding Marmot
Special Announcement

Thank you to everyone who made the drive up to Hatcher Pass yesterday for the 3rd Annual Hatcher Pass Avalanche Rescue Workshop! The next avalanche workshop will be this coming Saturday, Jan 21st at Turnagain Pass!! See those details HERE!


Photo: Thanks to the Hatcher Pass Snow Riders Club for hosting the workshop put on by Hatcher Pass Avalanche Center, CNFAIC, Alaska Avalanche School and the Alaska Avalanche Information Center!

 

  • Join CNFAIC for our final Fireside Chat on Thursday night, Jan 19th! Aleph Johnston-Bloom will discuss "how has the Turnagain Pass snowpack shaped up" and more - Details HERE.

 


The Bottom Line

The avalanche danger is MODERATE today in the mountains surrounding Turnagain Pass at elevations above 1,000' and on all aspects. Wind slab avalanches will be possible to trigger on slopes over 35 degrees that have been loaded by winds. These slabs are expected to be relatively soft, in the 1-2' thick range and could be lower on slopes due to cross-loading. Loose snow sluffs are also possible on the steeper slopes and these could run further than expected. 

*In the Girdwood Valley, where more snow fell on Friday, there is a heightened danger as a slab avalanche triggered could be 2-3' thick on wind loaded slopes. 


Primary Concern

It feels like a return to "what winter should be like" along the Eastern Turnagain Arm this weekend. Snow has been consistently falling after a two week dry spell, and to sea level for the first time in practically 4 years. Friday's snowfall numbers were confirmed yesterday to be 8-12" at Turnagain Pass, 7" at Johnson Pass, 7" at Ingram Creek at sea level and the winner, 15-18" in Girdwood Valley. Another round of snow is on the way currently and is expected to bring 2-3" today and another 4-6" tonight, at all elevations. These may not be the heavy Chugach Storms, but they are drastically improving riding and skiing conditions.

Avalanche activity yesterday, that we know of, was minimal. Human triggered sluffs and very small slabs were noted. Poor visibility limited a good look around for assessing natural avalanches that may have occurred during the storm. We had a number of folks mention 'possible crowns' seen on N facing Sunburst, NE facing Tincan (Todd's Bowl) and N facing Magnum. 

Andy Moderow captured this picture of Tincan Proper and Hippy Bowl yesterday in a moment of good light. Note the surface 'texturing' and drifting by the winds - a good way to determine likely wind loaded slopes vs. wind scoured.

 

A look at the West face of Magnum from the road in partically obscured light.


 

WIND SLAB:

Today's main concern are wind slab avalanches. Winds during the past 24-hours have been bumping into the moderate range along the ridgetops from a generally Easterly direction - this is just enough to form wind slabs in favored areas. The pattern will be the same again today. Although travel above treeline may be challenging with low visibility, if you do get to these areas, pay close attention to what the wind has done, or is doing to the snow. With plenty of loose snow to load slopes, it won't take much to form slabs 1-2' thick that could be quite touchy if they are fresh. These slabs are likely to be soft and could be lower on slopes where cross loading may have occurred. 

Red Flags to look for:

  1. Recent Avalanches
  2. Cracks that shoot out from your snowmachine, skis or snowboard
  3. A transition from soft snow to stiffer feeling snow when climbing to exposed areas or higher elevations affected by winds
  4. Texturing of the snow surface (may be difficult to see if an inch or two of new snow falls) 

 


Secondary Concern

Expect sluffs to be fast moving today on steep and sustained slopes that have a slick wind-hardened surface underneath. Sluffs will be composed of Friday's storm snow (8-12"). Cold temperatures yesterday and overnight have likely enhanced the potential for these loose snow avalanches in terrain approaching 40 degrees and more.


Additional Concern

Yes, we are still concerned about glide cracks releasing. Most of the cracks we know about are in areas rarely traveled. The exception is in -1 Bowl (Main Bowl) in the Seattle Creek drainage where glide cracks threaten terrain commonly traveled. Keep an eye out for cracks, which can be difficult with new snow, and limit time underneath them.


Mountain Weather

Yesterday was a break in between storms. Skies were mostly cloudy and snowfall stopped in the early morning - no accumulation in the past 24 hours. Ridgetop winds were light to moderate from a mostly Easterly direction. Temperatures dropped through the day as cold air was pushed in behind the storm system creating some valley fog. 

Today, the second (in a series of two) storm systems is moving in. This event looks to be much like last Friday's; take a look at the satellite image. Light snowfall has just begun and will continue into tomorrow morning. We should see anywhere from 2-3" today and 4-6" tonight (snow to sea level). Will Girdwood get more with this system as with the last? Possible, check back tomorrow morning! Ridgetop winds today are expected to increase to 10-20mph from the East and temperatures warm into the 20'sF at 1,000' and the mid-teens at the upper elevations.

Martin Luther King day and into the work week, a return to clearing skies, cold temperatures and a breezy Northwest flow is forecast.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 22   0 42 
Summit Lake (1400') 10  0 15 
Alyeska Mid (1700') 18  0.2  35 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 17  10  25 
Seattle Ridge(2400') 18  SE  15 

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
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