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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Thursday, April 4th 2013
Created: Apr 4th 6:52 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.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
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The John Byrne Family
Special Announcement

Are you going to Arctic Man this year?  Join Alaska Mining and Diving Supply, the Friends Group and CNFAIC Forecaster Graham Predeger for a free "Hoodoo Mountain Snowpack and Avalanche Assessment" field workshop on Wednesday afternoon!  Meet at the AMDS tent at 2PM for a fun and informative afternoon of snowpits and POW as we try and wrap our heads around what the primary avalanche concerns will be for the week!  Contact Graham at graham@chugachavalanche.org for more information.


The Bottom Line

Today will be a similar pattern as to what we’ve seen the last few days with warm daytime temperatures and direct sun contributing to a spike in the hazard late in the day.  The avalanche danger will start LOW this morning and increase to MODERATE on sun affected slopes as the afternoon wears on.  Furthermore, it will be prudent to avoid cornices today like the plague; this includes spending time in their looming shadows.


Primary Concern

Wet avalanches will again be our primary concern today likely becoming active on southerly slopes late in the day as the snowpack continues to absorb solar radiation, subsequently weakening the bonds between individual grains.  This is the “melt” process of the melt-freeze cycle.  Pay attention to the snow surface throughout the day.  Indicators of the avalanche danger rising will come in the form of point releases, roller balls on steep slopes and a boot penetration above your knees.  If you are seeing any of these signs it’ll be a good idea to avoid steep slopes on the south end of the compass, as these are all indicators of our snowpack losing strength. 

As seen in this photo below, sun induced slabs are also of concern this week.  These have been relegated to the upper most layer of our snowpack with no signs of stepping down into older snow, though a potential for wide propagation exists.


Secondary Concern

Today will be the 5th day in a row of a melt-freeze cycle with cornices undergoing the same diurnal changes as the snowpack.  Once the day heats up and individual snow bonds weaken, cornices will be more likely to fail spontaneously.  As was the case on Goat Mountain (Girdwood Valley) Tuesday, cornice failure may trigger a slab avalanche once it fails, neither of which you want to be involved with today.  Continue to use good judgment around cornices and avoid prolonged exposure, specifically late in the day. 

 

 

ADDITIONAL CONCERNS

There is still some uncertainty on northerly slopes where shallow wind slabs have been found to be reactive on buried surface hoar and near surface facets.  The good news is that our mid-pack is showing respectable signs of strength and wind slabs from last weeks storm don’t appear to be stepping down into deeper layers.


Mountain Weather

Yesterday was another beautiful spring day in the backcountry.  SE winds in the teens and low 20’s kept the snow surface cool enough that we didn’t experience much avalanche activity. 

Today looks to be another warm day on tap with temperatures reaching mid-40’s at 1000 feet and winds very light out of the east.  Direct sun and less wind than yesterday will contribute to a rise in the avalanche danger this afternoon.  No precipitation is expected to fall today.

Temps will again fall overnight though they may not rebound quite as high as we’ve seen this week as a colder air mass begins to move into our area from northwestern Canada.


Kevin will issue the next advisory on Friday, April 5th. 

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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