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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Monday, January 28th 2013
Created: Jan 28th 6:13 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.
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.
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The Bottom Line

The avalanche hazard is MODERATE above treeline today, where wind slabs will become more sensitive to human triggers with a slight rise in temperatures.  Deep slab avalanches are still a concern above treeline as well.  Below treeline the hazard is LOW, where recent cold temperatures have helped to solidify much of the snowpack.


Primary Concern

Wind slabs formed over the past several days of sustained light to moderate winds are the primary concern today.  Look for these slabs to be relatively shallow, less than a foot in depth and sitting in potentially unusual areas (e.g. mid slope, well below and away from ridgelines).  Recent winds have created shallow slabs that were sensitive to human triggers over the last two days.  In the higher elevations much of the snow that was available for transport has been either scoured or turned into these stiff slabs.  The chance of new wind slabs forming today are on the low end because of this lack of snow available for transport.  The wind slabs we observed being triggered this weekend pulled out in steeper terrain, generally above 35 degrees and on average closer to 40 degrees.  A rise in temperatures today will increase the sensitivity of these slabs.  Be on the lookout today for these pockets of lingering slabs, especially above cliffbands, gullies and trees.  While these avalanches are generally low in volume, consequences go up when one of these pockets sweeps you into or over a terrain trap.


Secondary Concern

The deep slab problem continues to linger.  This problem has gone from being a widespread issue to one that exists primarily above treeline.  Warm temps and light rain last week melted the snow surface and penetrated to the lower layers of the snowpack.  These melted layers have now had time to go into a hard freeze and are much stronger.  Above ~2,000' this process has not occurred to the same extent.  Therefore, it is worth remembering that the weak snow that formed in the beginning of the season still lurks below.  The likelihood of triggering a deep slab today is low.  The consequences of triggering an avalanche in weak layers buried 3-8 feet deep are still potentially high.


Mountain Weather

Clear and cold conditions dominated the region over the weekend.  The Sunburst weather station at 3,800' reached -17 degrees F overnight.  Winds have been light to moderate during this time, primarily out of the North, Northwest and West.  No precip has fallen over the last several days.

Look for temps to begin climbing today as a low pressure system centered to South of the Aleutians makes its way towards South Central Alaska.  Temps will reach into the teens by midday, clouds will move in and just a trace of snow will fall during the day today.  Winds will shift from West to East and will be 10-15 mph with gusts to 30mph.

A greater chance for snow will come tonight and into tomorrow.  Temperatures will continue to rise into the 20s and 30s into the middle part of the week.  A chance of snow exists each of the next three days in our area.

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Wendy will issue the next advisory tomorrow morning, January 29th.

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 15, 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: Open
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

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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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