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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Monday, February 17th 2014
Created: Feb 17th 6:25 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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.
 Show the Complete North American Avalanche Danger Scale
Special Announcement

 - Update 11:30 am -

Motorized access via Turnagain Pass and Johnson Pass on the Glacier Ranger district of the Chugach National Forest are now OPEN.  Check the bottom of this page for the latest updates on riding area status and conditions as well as the Chugach National Forest website.


The Bottom Line

The avalanche hazard is CONSIDERABLE today above treeline.  Slabs up to 3’ in depth could be remotely triggered by humans in steep upper elevation terrain.

Below treeline the hazard is MODERATE.  It will be possible for people to trigger loose snow sluffs & isolated pockets of slabs up to a foot in depth in steep terrain in the lower elevations today.


Primary Concern

The late January onslaught of rain and high temps was followed by a period of clear and cold weather.  At the tail end of this January storm a small amount of snow fell in the higher elevations.  That thin layer of snow sat on a stout slick crust for almost ten days.  During that time this layer grew weak.  Between Feb 7th and today over 36” of snow has fallen on top of this weak layer in the higher elevations.  In areas where this weak layer exists, mainly above 3,000’ and in some places above 2,000', the potential for slabs up to 3’ in depth could release from the weight of a person.

This issue is a tricky one to detect.  Because the distribution of this weak layer is not uniform, it is difficult to know with confidence whether that weak layer is lurking below you or not.  It should be assumed that this combo is present above 3,000’.   This problem reared its ugly head yesterday with multiple parties reporting remotely triggered avalanches throughout the forecast area. Click for Eddie's avalanche, Twin Peaks avalanche & Tenderfoot (Summit Lake area) avalanche.

Eddie's remote

The best way to manage this problem today is to simply avoid terrain over 35 degrees in the higher elevations.  You might be able to get away with skiing steeper terrain, but it is a roll of the dice given the current conditions.


Secondary Concern

Another modest batch of precipitation will refresh the riding conditions.  It will also require being on the lookout for issues related to storm snow instabilities.

Loose snow avalanches
These will be generally low volume but easy to trigger in terrain over 40 degrees.  This problem is one that becomes more serious when traveling above terrain traps such as trees, gullies and cliff bands.

Storm Slabs & Wind Slabs
It will be possible for humans to trigger newly formed slabs in steep terrain today.  Winds have been relatively light but enough to create new slabs up to a foot in depth.  Sticking to terrain 35 degrees and under, especially on leeward upper elevation slopes will be the best way to avoid this problem today.


Additional Concern

Cornices continue to grow and build above many starting zones.  Give cornices a wide berth when traveling along ridge crests.  Pay attention to the terrain above you as well.  If you find your group below cornices spread out and only expose one person at a time.


Mountain Weather

In the past 24 hours the mountains around Eastern Turnagain Arm have picked up ~5” of new snow with ~.3” of snow water equivalent.  Ridgetop winds have been out of the East at 12 mph with gusts to 38 mph.  Ridgetop temps have averaged in the single digits F and have been gradually climbing overnight into the low teens F.

Today expect snow showers to continue through the morning hours with potential for clearing skies by the afternoon.  Snow accumulations of 2-4” are possible.  Winds will be light out of the East at 5-10 mph.  Temperatures at 1,000’ will climb into the high teens to low twenties F.

The massive upper level Low pressure system that has been parked over much of the state will continue to bring alternating bands of precip and clear skies until tomorrow.  That system will begin to break down beginning late tomorrow.  Expect more precip and rising temperatures as we head into the middle part of the week.

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

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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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