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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Saturday, April 6th 2013
Created: Apr 6th 5:49 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 LOW above and below treeline.  New snow amounts will be relatively light today.  However, shallow pockets of new slab will form and be easy to trigger in steep upper elevation terrain.  It is in these areas where the avalanche hazard will inch up to the MODERATE range very late in the day.


Primary Concern

Small slabs will be easy to trigger by the end of our long day today (sunset will be at 9pm tonight).  Snowfall will pick up later in the day.  Prior to new snow falling it is always a good practice to know what the snow surface is comprised of.  Yesterday south facing and low elevation slopes melted during the day and froze overnight.  North facing slopes in the upper elevations were holding pockets of small surface hoar.  As this "drought layer" gets buried it will need to adjust to the new snow falling onto it.  Surface hoar will not allow new snow to bond to it very well.  Neither will crusts.  If the new snow comes in warm, as it is forecasted to do, bonding will be better.  Shallow wind slabs will build by this evening in isolated pockets and are worth avoiding on steep north through west facing aspects.


Secondary Concern

While the snowpack is stable in many areas, there are a few things to consider today when making decisions.

Loose Snow Avalanches

Yesterday my partner and I found surface hoar on steep high elevation north facing slopes.  This surface will prevent new snow from sticking to it well.  Because of this, low volume sluffs will run fast and readily in this type of terrain.  While the volume will be too low to be a problem on its own, things can change for the worse when these small avalanches occur while you're above cliffbands, gullies or trees.

 

Cornices

While today is not a prime day for cornices to come crashing down, it is still worth remaining vigilant in the presence of these large masses of snow.  Give them plenty of room when approaching ridgecrests and while travelling below them.


Mountain Weather

In the past 24 hours the Sunburst weather station at 3,812' reported an average temperature of 20 degrees F.  Winds were calm to light, blowing 4 mph out of the SW.  No measurable precip has fallen.

Light snow showers have begun this morning.  Today expect up to 6" of new snow.  Ridgetop winds will be light out of the SE at 10-15mph.  Temperatures at 1,000' will be in the low 30 F range.

The pattern of clear and sunny weather is over.  An unsettled pattern is on tap for the next several days, with precip, cloud cover and cooler temps on its way.

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I will issue the next advisory tomorrow morning, April 7th.

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 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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.


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