Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sat, December 29th, 2012 - 7:00AM
Expires
Sun, December 30th, 2012 - 7:00AM
Forecaster
Kevin Wright
Avalanche risk The Bottom Line

A short break in stormy weather gave us a good look around the mountains yesterday.   Widespread natural avalanche activity confirmed the avalanche warnings we’ve been issuing most of the week.   Today, another storm is starting to hit us, bringing us into another upswing in the avalanche danger.   HIGH avalanche danger can be found on most aspects and elevations today due to new snow, high wind, and rising temperatures.   Travel is not recommended in avalanche terrain or anywhere in a potential runout zone.

This photo of Eddies from yesterday illustrates the problem we are dealing with.   Similar avalanches may be triggered by skiers or snowmachiners today.   The 3-4 foot depth will be dangerous and unmanageable.

Eddies natural avalanches 12-28-12

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Sat, December 29th, 2012
Alpine
Above 2,500'
High (4)
Avalanche risk
Treeline
1,000'-2,500'
High (4)
Avalanche risk
Below Treeline
Below 1,000'
High (4)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
High (4)
Treeline
1,000'-2,500'
Avalanche risk
High (4)
Below Treeline
Below 1,000'
Avalanche risk
High (4)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • 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 is cranking at ridge tops this morning.  All the new snow from earlier in the week will be loading the lee slopes to failure today.  Natural avalanches are expected in wind loading terrain.  

Early this morning we’ve seen 4 hours of 1 inch per hour snowfall and wind speeds averaging 31-62mph overnight.  Wind slabs are forming, and they may step down into deeper layers 3-4 feet deep.

Avalanche Problem 2
  • Deep Persistent Slabs
    Deep Persistent Slabs
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
More info at Avalanche.org

The deep slab on top of extremely weak faceted snow is a dangerous combination this weekend.  The photo of Eddies above gives a good perspective of the deep slab problem.  A lot of people consider Eddies to be appropriate “storm day” skiing on days with elevated avalanche hazard.  Unfortunately, right now even smaller lower angle slopes are avalanching in a deep and dangerous way.  Very conservative terrain management this week has kept everyone safe so far.  With continued stormy weather, that mandate continues for at least the next few days. 

Weather
Sat, December 29th, 2012

3-4 feet of new snow this week already caused a lot of natural avalanche activity.   Another wave of precipitation is reaching us this morning combined with high wind.   Temperatures are also warming higher than we’ve seen in a month, bringing the rain/snow line to 800 feet.  

Precipitation today is expected to taper off this morning, but wind reaching 80mph+ will be enough to increase avalanche activity.   Tonight and tomorrow the snowfall is expected to pick up.


Wendy will issue the next advisory Sunday morning December 30th.

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Riding Areas
Updated Tue, April 20th, 2021

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
Open
No parking in turnaround at end of the road near the outhouse.
Placer River
Open
Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
Skookum Drainage
Closed
The Skookum Valley is closed to snowmachines. This closure occurs annually on April 1 as per the CNF Forest Plan.
Turnagain Pass
Open
Twentymile
Closed
Seward District
Carter Lake
Open
Lost Lake Trail
Open
Primrose Trail
Open
Resurrection Pass Trail
Closed
Closed for the 2020/21 winter season.
Snug Harbor
Open
South Fork Snow River Corridor
Open
Summit Lake
Open

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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.