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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, February 3rd 2015
Created: Feb 3rd 6:09 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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Special Announcement

The Bottom Line

Most terrain in the Turnagain Pass and surrounding regions has a LOW avalanche danger. Exceptions are isolated older wind slabs sitting on weak snow. These will most likely be found in areas that have seen wind in the past week and can be identified by a stiff and smooth surface. 


Primary Concern

Today marks the 18th day since the last significant precipitation has fallen in the Eastern Turnagain Arm area. Since then, we have had a few inches of snow fall here and there. Otherwise, cold and clear weather has been stabilizing the snowpack and loosening the snow surface.

The main issue avalanche-wise are the interesting wind patterns during the past week of high pressure. Very localized winds from all directions have moved the loose surface snow around enough to form wind slabs in scattered zones. These are not found everywhere, but should be on our radar nonetheless. One of these was found and triggered by a party two days ago in the Seattle Creek drainage. Of note for this slab was its lower elevation location (2,400'). Often these types of slabs are relegated to the higher terrain. That said, surface instabilities to watch out for:

Wind Slabs:
Shallow wind slabs have been found scattered about in exposed areas, including mid-elevation terrain. Keep an eye out for changing surface texture and areas where the snow is smooth, stiff and may have a hollow feel. These areas should be relatively easy to identify since much of the surface is soft. Committing rocky and steep terrain will be the most concerning place to find a slab; as once you identify it, avoiding it could prove challenging. 

Loose Snow Avalanches:
Cool temperatures and clear skies continue to loosen and facet the snow surface. Sluffs on steep slopes, > 40 degrees, should be expected, though remain relatively low volume and manageable.


Additional Concern

Weather - or lack thereof, rather - could be called an "additional concern" for many of us, eh? Maybe not in the avalanche sense, but in the psychological one. Below are a couple charts illustrating the season's snowpack to date. These data are taken from the Turnagain Pass Snotel station on Center Ridge at 1880'. Roughly, we have 1/3 the snowpack we normally do this time of year. At the lower elevations, 1,000' and below, anyone that has been out will know it is mush less than this.

Caution: Look and digest graphs below at your own risk! 

 

 

A bit more of a write-up and graphs can be found HERE.


Mountain Weather

Yesterday was marked by sunshine, light and variable ridgetop winds and temperatures in the mid 20's F. Overnight, winds have shifted to the Northwest and climbed into the 5-10mph range.

Today, we should see sunny skies once again with temperatures in the mid 20's F at all elevations except for valley bottoms where colder air is pooling. Winds are forecast to remain in the 5-10mph range from the Northwest.

As for the future? Snow? This remains out of the foreseeable future. The very persistent ridge of high pressure over us will continue its strong hold. Sunny skies are in store for over a week from now. The outflow winds associated with the high pressure will the wild card for this week and into the weekend. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24  32 
Summit Lake (1400') 11   0  7
Alyeska Mid (1700') 24  20 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 25  var  10 
Seattle Ridge(2400') 24  16 

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
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