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Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, February 2nd 2015 6:51 am by John Fitzgerald
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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BROUGHT TO YOU BY
The Bottom Line

The avalanche danger is generally LOW around the forecast area.  Pockets of MODERATE danger exist on steep previously wind loaded slopes.  It is in this terrain where it will be possible for humans to trigger old wind slabs 8-10” in depth.

Yesterday skiers triggered a shallow slab avalanche around 2,400’ on an East aspect in the Seattle Creek drainage.  Fortunately both members of the party were not injured or buried.  Read HERE for more details, and see photo below.  This is a good reminder that LOW danger does not mean NO danger.  Pockets of unstable snow exist despite the generally unreactive nature of the snowpack around the forecast zone.


 Show the Complete North American Avalanche Danger Scale
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'
Special Announcement

Avalanche Problem 1

With a lack of significant weather over the past 2 weeks, we have seen very little avalanche activity.  Triggering an avalanche is unlikely around much of the forecast area.  Exceptions to this can be found in the following forms:

Old wind slabs
Yesterday’s skier triggered avalanche shows us that it is possible to find pockets of unstable snow.  With only occasional slight bumps in the wind over the last week, slabs that have formed are few and far between.  Localized winds have formed shallow slabs that are sitting on weak snow.  In the mid elevations that weak snow is sitting on a crust, creating the perfect slab/weak layer/bed surface combo.  If venturing into big steep terrain be on the lookout for snow that is stiff or hollow sounding.

Photo below of an avalanche triggered by skiers while bootpacking on the lower flanks of Big Chief in upper Seattle Cr drainage.  2,400' E facing slope.  100' across, 200' vertical. Photo: Billy Finley

Big Chief Skier triggered

Loose Snow Avalanches
Yesterday my partner and I were able to initiate very shallow sluffs in steep terrain.  The volume of these sluffs was very low and they were fast moving.  In sustained steep terrain pay attention to snow that releases from your feet, as it has the potential to knock you over.

With these issues in mind, it is important to avoid complacency by following safe travel protocol:
-Travel one at a time on suspect slopes
-Use islands of safety for spotting or re grouping
-Have an escape route planned prior to committing to a slope
-Communicate decisions and plans well with your partners
-Watch for other groups and avoid exposing yourself and others to avalanche hazard


Mountain Weather

Clear skies prevailed again yesterday.  Ridegtop temperatures were mild, in the low 30s F.  Some valley locations experienced an inversion where temperatures remained in the teens F through the day. Winds were generally light.  No new precipitation was recorded.

Today looks to be very similar as high pressure remains over the area.  Temperatures along ridgetops will be in the high 20s F.  Some valley locations will experience a steep inversion and will see temps in the single digits/teens F.  Winds will be light out of the West.  

The ridge of high pressure that is parked over much of the state will shift its position slightly this week, but not enough to bring about a change.  Temperatures will drop slightly later in the week as cold air moves in from the North.  Clear and dry conditions look to remain in place through the work week.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28 0 0 31
Summit Lake (1400') 13 0 0 7
Alyeska Mid (1700') 26 0 0 21

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 33 E 5 15
Seattle Ridge(2400') 31 var 4 17

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 06, 2018 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed as of April 20th
Placer River: ClosedClosed as of April 17th
Skookum Drainage: ClosedClosed as of April 1st.
Turnagain Pass: ClosedClosed as of May 7th. Happy summer, see ya when the snow flies!
Twentymile: ClosedClosed as of April 13th
Seward District
Carter Lake: ClosedClosed as of 4/27
Lost Lake Trail: ClosedClosed as of April 13th
Primrose Trail: ClosedClosed as of April 13th
Resurrection Pass Trail: ClosedClosed as of April 20th
Snug Harbor: ClosedClosed as of 4/27
South Fork Snow River Corridor: ClosedClosed as of April 13th
Summit Lake: ClosedClosed as of April 20th

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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