Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, March 9th, 2013 - 7:00AM
Expires
Sun, March 10th, 2013 - 7:00AM
Forecaster
Graham Predeger
The Bottom Line

The last couple days brought a refresh of snow to Turnagain Arm and increased the avalanche potential.   Storm snow and high wind caused a spike in the danger yesterday.   Since then the snowpack has had some time to adjust, but we can still expect the upper end of MODERATE danger above treeline where highest storm totals can be found along with a lot of wind loading from 100+mph wind 2 nights ago.  

Given 1-2 feet of new snow in some areas, extra caution should be taken in the mountains today while the snowpack continues to adjust to that new load.

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Sat, March 9th, 2013
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
Moderate (2)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Moderate (2)
Treeline
1,000'-2,500'
Avalanche risk
Moderate (2)
Below Treeline
Below 1,000'
Avalanche risk
Moderate (2)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at Avalanche.org

The 2 day storm total has brought more than 2 feet of snow to upper elevations in the Girdwood valley (Alyeska).  Turnagain Pass seems to have gotten about 75% of that amount.  The storm was warmer than we’ve had recently with rain up to about 500 feet elevation.  Areas below treeline will have denser snow, which dries out the higher you climb. 

We have no reports of unusual avalanche activity from this storm.  All reported avalanches yesterday were of predictable size and character corresponding to the storm event.  Given warmer temperatures and a relatively strong and stable snowpack before the storm hit, our primary concern is the 1-2 feet of storm snow sliding at the new/old snow interface.  This means we aren’t very concerned about deeper avalanches.  It also means that we expect bonding to happen relatively quickly. 

We are still within 24 hours of the storm event.  Avalanche 101 protocol tells us that we are still in a higher probability time to trigger avalanches.  Today there is plenty of moderate angle terrain to enjoy the new snow, but big gaming should be delayed another day or two to allow the new snow to settle out and stabilize. 

Avalanche Problem 2
  • Wind Slabs
    Wind Slabs
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at Avalanche.org

Wind driven storm snow will be deepest on west and northwest aspects today with crossloading on north and south.  Peak wind was 2 nights ago, corresponding with some of the highest intensity snowfall.  Wind diminished yesterday but stayed strong enough to continue blowing snow around.  Any avalanche found today will likely have a wind loaded component to it.  Deeper and stiffer snow should be treated with more suspicion than soft and loose powder. 

Cornices have been a big issue for us over the last several weeks, and given more snow and high wind we can expect larger and less stable cornices again this weekend. 

Weather
Sat, March 9th, 2013

2 day storm totals    

Alyeska top – 28+ inches snow – 2.54 inches of water equivalent

Alyeska mid – 24 inches snow – 1.7 inches water equivalent

Turnagain Pass – 10-12 inches snow est – 0.8 inches water equivalent

Grandview – 0.6 inches water equivalent

Weather today will bring snow showers with 1-3 inches expected.   As this storm system moves through the wind will continue to drop, and temperatures should decrease by a few degrees.  

There is no sun in the forecast this weekend, but clear and colder weather is expected starting Monday.


Wendy will issue the next advisory on Sunday, March 10th.

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Riding Areas
Updated Mon, October 26th, 2020

Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: mailroom_r10_chugach@fs.fed.us

Area Status Weather & Riding Conditions
Glacier District
Johnson Pass
Closed
Placer River
Closed
Skookum Drainage
Closed
Turnagain Pass
Closed
Twentymile
Closed
Seward District
Carter Lake
Closed
Lost Lake Trail
Closed
Primrose Trail
Closed
Resurrection Pass Trail
Closed
Snug Harbor
Closed
South Fork Snow River Corridor
Closed
Summit Lake
Closed

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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.