Mon, January 07, 2013 Turnagain Pass Avalanche Forecast

Mon, January 7th, 2013

Alpine
Above 2,500'

Considerable (3)

Treeline
1,000'-2,500'

Considerable (3)

Below Treeline
Below 1,000'

Considerable (3)

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

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

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

Deep Slabs continue to be our biggest threat. With snowfall amounts moderating over the past several days, the undetectable nature of this problem has increased. However, moderate loading in the past 24 hours coupled with more precip forecasted for today, should increase the chances of pulling out one of these deadly slides. Large natural avalanches are still possible today, as we have seen a continuation of natural avalanche activity over the past several days. The challenge now is that many areas might be able to support the weight of potentially an entire group of skiers or snowmachiners. All it takes is finding the wrong spot (thinner parts of a slab) to create serious problems. Avoiding likely trigger points, slopes over 35 degrees, and big open terrain is the best way to tiptoe around this dangerous and persistent problem.

Avalanche Problem 2

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

While 10″ of new snow is enough of a load to be a concern, the bonding of new storm snow to the surface has been good of late. Look for fresh new wind slabs to be reactive to the weight of a person or snowmachine today. While these slabs don’t carry the same consequences as a deep slab, they warrant attention, as they can entrain enough snow on their own to injure or bury a person. These wind slabs also have some potential, once released, to pull out deeper weak layers. Look for this problem to be more prevalent above treeline today.

Weather

Mon, January 7th, 2013

In the past 24 hours Turnagain Pass has picked up 10″ of new snow with 1″ of water. Ridegtop winds have averaged 25 mph out of the East with gusts to 52. Temps at 3800 feet have averaged in the low 20s with freezing levels hovering between sea level and the 500 foot elevation.

A slow moving low pressure system over us today will produce up to 8″ of new snow, winds out of the East at 20-40 mph and temps at 1000′ around 30 degrees F.

The pattern of unsettled weather should continue later in the week, with a break in the action tomorrow and Wednesday.

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Wendy will issue the next advisory tomorrow morning, January 8th.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/28/22	Turnagain	Avalanche: Turnagain Pass – late May wet slab cycle	CNFAIC Staff
05/21/22	Turnagain	Avalanche: Magnum, Lipps and Tincan	CNFAIC Staff
05/17/22	Turnagain	Avalanche: Sunburst	CNFAIC Staff
05/17/22	Turnagain	Observation: Tincan Ridge	Joe Kurtak
05/11/22	Turnagain	Avalanche: Cornbiscuit and Magnum west faces	CNFAIC Staff Forecaster
05/07/22	Turnagain	Observation: Granddaddy	Kit Barton
04/29/22	Turnagain	Observation: Sunburst wx station	AS/ MM/ AM/ NH
04/28/22	Turnagain	Observation: More Turnagain Pass/Summit Lake wet slab activity	Alex Marienthal
04/27/22	Turnagain	Observation: Magnum	Sykes / Buttrick Forecaster
04/27/22	Turnagain	Observation: Girdwood/Summit/Turnagain Road obs	A S

Riding Areas

Updated Wed, June 01st, 2022

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	Closed as of May 1 per Forest Plan.
Placer River	Closed	Closed as of April 25th due to insufficient snow coverage.
Skookum Drainage	Closed	Closed as of April 1st per Forest Plan.
Turnagain Pass	Closed	Closed as of June 1st.
Twentymile	Closed	Closed as of April 6th due to insufficient snow coverage.
Seward District
Carter Lake	Closed	Closed as of May 1 per Forest Plan.
Lost Lake Trail	Closed	Closed as of May 1 per Forest Plan.
Primrose Trail	Closed	Closed as of May 1 per Forest Plan.
Resurrection Pass Trail	Closed	Closed as of May 1 per Forest Plan.
Snug Harbor	Closed	Closed as of May 1 per Forest Plan.
South Fork Snow River Corridor	Closed	Closed as of May 1 per Forest Plan.
Summit Lake	Closed	Closed as of May 1 per Forest Plan.