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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, January 11th 2015
Created: Jan 11th 5:58 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.
0 NO RATING Below Treeline / Below 1,000'
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The Bottom Line

The avalanche danger remains LOW at all elevations in the forecast zone where triggering an avalanche will be unlikely. However, naturally occurring glide avalanches are possible as glide cracks have been opening recently. It is key to recognize and avoid being under these cracks (photos below). In steep terrain above 4,000' where dry snow exists, pockets of unstable snow may be found - most likely in the form of stiff wind slabs.

Once again, the main hazard in the backcountry will be negotiating hard and slick snow surface conditions along with rocks, stumps, overflow ice, etc.


Primary Concern

I think the word is out that Turnagain Pass is not the place to find powder snow - this weekend anyhow... After a very warm storm rolled through Thursday saturating much of the snowpack up to 2,500' and the surface layers up to 3,500', the pack is slowly freezing from the top down. The rain wiped out much of the snow below 1,500' and hiking is required from the parking lots at the Pass. Above 1,500', the snowpack does get deeper quickly, but it's the surface conditions that are the challenge. In short, the surface crust is mostly supportable, hard and slick. Beware that steep slopes have a slide-for-life character.

Where the crust ends and the soft snow begins is likely around 4,000'. If you are headed to these high elevations, assessing the snowpack is key. Keep your eye out for weak snow, such as buried surface hoar or facets, sitting under stiffer slabs. Finding a slab avalanche, most likely a wind slab, in these more remote and high elevations is possible. 

For more details on snowpack and surface conditions, check out the several observations sent in yesterday from a level 2 avalanche course in the neighborhood. Thanks Alaska Avalanche School!


Secondary Concern

Many glide cracks continue to open up in the forecast zone. During the day yesterday several new cracks were seen opening as well as existing cracks widen. None were reported to have avalanched but one avalanche instructor commented "We would not want to be below these glide cracks right now!". That said, these are easy to recognize and avoidance is the best tactic considering their unpredictable nature and destructive potential. This is not the kind of avalanche a person can trigger, rather would be a case of being in the wrong place at the wrong time. 

Photo below: Two avalanche students inspect a freshly open glide crack on Tincan ~2,800' South facing. Notice the additional cracks further along the subridge. (Photo credit: Eeva Latosuo)

Photo below is of three "brown frowns" that have opened in the pat 48-hours (Eeva Latosuo).


 


Mountain Weather

Yesterday was a mild day in the backcountry with partly cloudy skies, light Easterly winds and temperatures in the mid 30's F at the mid elevations and low 30's on the ridgetops. There has been no precipitation since Thursday's 0.5-1" of rain up to 3,000'.

Another mild day is in store for today. We should see partly cloudy skies with a slight bump in the Easterly ridgetop winds, into the 15mph zone. Temperatures look to remain near 30F on the ridgetops and the mid 30's F at the mid and lower elevations.

Our next shot for precipitation is expected to arrive tomorrow afternoon in the form of rain below 2,500' or so. This system will again usher in warm and windy conditions with moderate precipitation amounts. Stay tuned.

Looking further into the crystal ball (weather models) for later in the week and into the weekend, we will see a series of low pressure systems in the Gulf move through with showery precipitation. Slightly cooler temperatures are expected for Friday, which will help to lower the rain/snow line. However, warmer air looks to follow right behind for Saturday into Sunday, keeping the rain/snow line in the 2,000' zone.

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 36  0 29 
Summit Lake (1400') 29 
Alyeska Mid (1700') 37  0 22.5 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 31   26 
Seattle Ridge(2400') 33  NE  12   27

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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to 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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