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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Thursday, February 5th 2015
Created: Feb 5th 5:53 am
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'
 Show the Complete North American Avalanche Danger Scale
Alaska Rock Gym
Special Announcement

Iron those Carhartts, break out the sequins, and dust off the bolo…its Snowball time! Please join the Friends of the Chugach National Forest Avalanche Information Center and Alaska Avalanche School at Taproot for an “Alaskan Formal” night at 7pm on February 27th.  More details on this spring FUNdraiser can be found here.


The Bottom Line

LOW avalanche danger exists in Turnagain pass and most of the surrounding region.  However, LOW does not mean NO avalanche danger.  Shallow wind slabs sitting on weak snow can be found scattered throughout the Pass and periphery areas and identifiable by a stiffer, smooth surface.

Winds are expected to kick up to the low 20’s mph from the North late in the day.  If these winds come earlier or are stronger, expect slabs to still be shallow but rather easy to initiate.


Primary Concern

This persistent high pressure weather pattern is reminiscent of the in-laws that have stayed past their welcome.  Sure everybody loves sunshine and mild temps for a few days or even a week, but we yearn for a change in house guests eventually.  I think that most can agree that we are ready for rowdy Old Man winter to come and “crash the couch” for a bit this month!

In the meantime this high pressure is allowing the brave and adventurous among us to venture through the Forest, past the Alder-wall and high into the Alpine.  For those that make it, rewards have come in the form of generally stable snow and soft surface conditions.  That being said, pockets of instabilities may exist in the form of shallow wind slabs and loose snow avalanches.

Wind Slabs:

Shallow wind slabs have been found littered throughout the advisory area in the mid and upper elevations.  As most of the surface is quite soft (comprised of near surface facets or ‘loud powder’) these wind slabs are fairly easy to identify by feel as the surface below your skis will feel stiff or hollow.  These older wind slabs are very likely to be small (<6”) and manageable if initiated. 

Winds are expected to pick up today and intensify tomorrow and into the weekend creating more widespread (though still shallow) wind slabs and some bitterly cold wind chills.

Loose Snow Avalanches:

We’ve had yet another day of weather that has aided in loosening and faceting the snow surface.  Sluffs on steep terrain, > 40 degrees is low in volume but fast moving.  Anticipate this, manage it accordingly and it shouldn’t prove much of an issue today.

Loose snow sluffs are fast moving but managable.  photo: Wendy Wagner


Mountain Weather

Calm, cool and clear describe yesterday’s weather in the Turnagain pass area.  Inverted temperatures continued with single digits at the highway and low 20’s at ridgetops yesterday.  Winds were light out of the west and as soon as you began climbing the Seward highway into Turnagain pass, the low-level fog parked in the Arm was a distant memory with blue sky abound above about 300’.

The potential game-changer today and into the weekend will be the onset of moderate northerly winds starting out calm this morning and increasing into the low 20's by this afternoon/ evening. These winds are fueled by a tightening pressure gradient between a low in the Gulf and the dominant high pressure over mainland Alaska. Any wind today should act to scour out a mild temperature inversion and low level fog by this evening.  Temps are expected to be reach the mid-20's by this afternoon under clear skies.

Cold, clear and windy looks to continue through the weekend as dry offshore flow continues to dominate southcentral Alaska at least through Sunday morning.  Expect wind chill values to be well below zero by tomorrow.  The National Weather Service is hinting at a pattern change by mid-week next week as the Bering High moves west into Russia promoting southern flow and an increased chance of precipitation.

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 18   0  0  31
Summit Lake (1400')  7  0  7
Alyeska Mid (1700')  19  0  20

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 20   6  12
Seattle Ridge(2400')  18  Var. 11 

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.


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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