Sat, January 04, 2014 Turnagain Pass Avalanche Forecast

Sat, January 4th, 2014

Alpine
Above 2,500'

Considerable (3)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

Moderate (2)

Alpine Above 2,500'		Considerable (3)
Treeline 1,000'-2,500'		Moderate (2)
Below Treeline Below 1,000'		Moderate (2)

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

Persistent Slabs

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

More info at Avalanche.org

A busy couple days in the backcountry brought a lot of avalanche activity through Turnagain Pass and Summit. On Thursday a group of skiers triggered at least 5 disconnected avalanches remotely from the ridge (See color picture below). Yesterday, a dog triggered an avalanche on the lower part of Tincan ridge (black and white photo below). Despite the search efforts of at least a dozen people, the dog was not found and is presumed dead. For reference, this is the same slide path that slid almost exactly a year ago.

Other reported avalanches include – Eddies, south and west aspects, Sunburst – SW aspect, Seattle ridge – Bowl 2. (Click on links to go to observations and more photos)

These avalanches are sliding on older and deeper weak layers. Once they get moving the entire depth of the snowpack can get stripped out. They are unmanageable in size, will trigger remotely, and can connect across large distances.

Terrain management is key to safe travel this weekend. This means stay off steep slopes and avoiding terrain traps and complex terrain.

Black and white photo – lower CFR, Tincan ridge. Crown at 2300 feet elevation

Upper Tincan ridge. Crowns near 3500 feet elevation.

Avalanche Problem 2

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

New storm snow will exacerbate the persistent slab problem today as new stress gets added to the snowpack. By late today, the storm snow on its own may be deep enough to be its own distinct problem.

With over a foot of snow expected (possibly 2+ feet), we can expect natural avalanche activity to start late today and continue over night. We will likely reach HIGH avalanche danger during the peak of this storm.

Weather

Sat, January 4th, 2014

The last major storm was over the Dec 31st/Jan 1st holiday. Since then conditions have been mild and pleasant.

A big change is in the forecast today. A powerful storm is directing a moisture laden southern jet stream from warm lower latitudes straight at southcentral Alaska. The picture below describes the scenario far better than I could in words.

Snowfall is expected to start this morning and increase in intensity this afternoon and into the evening. Wind will be associated with this storm with a ridgetop wind from the East at 56-73mph. Rain at sea level is expected, transitioning to snow at 300-400 feet. Storm totals are predicted in the 16″-29″ range for the next 24 hours.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/22/23	Turnagain	Avalanche: Tincan	Nick D'Alessio
05/12/23	Turnagain	Avalanche: Tincan, Sunburst, Magnum, Cornbiscuit	Heather Thamm
05/07/23	Turnagain	Observation: Tincan – Bear Tracks	CNFAIC Staff
05/05/23	Turnagain	Observation: Seattle Ridge	AS/ WW Forecaster
05/02/23	Turnagain	Observation: Cornbiscuit	Schauer/ Sturgess Forecaster
05/02/23	Turnagain	Observation: Seward Hwy Turnagain Pass	Joel Curtis
04/30/23	Turnagain	Observation: Magnum	Ayla, Kit Crosby, Barton
04/29/23	Turnagain	Observation: Tincan	John Sykes
04/28/23	Turnagain	Avalanche: Taylor Pass/Pastoral	Schauer/ Creighton Forecaster
04/28/23	Turnagain	Avalanche: Tincan	Andy Moderow

Riding Areas

Updated Sat, September 23rd, 2023

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	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Placer River	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Skookum Drainage	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Turnagain Pass	Closed	Scheduled opening on the Wednesday before Thanksgiving per Chugach National Forest plan. Subject to adequate snow cover.
Twentymile	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Seward District
Carter Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Lost Lake Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Primrose Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Resurrection Pass Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Snug Harbor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
South Fork Snow River Corridor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Summit Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.