Tue, January 01, 2013 Turnagain Pass Avalanche Forecast

Tue, January 1st, 2013

Alpine
Above 2,500'

High (4)

Treeline
1,000'-2,500'

High (4)

Below Treeline
Below 1,000'

High (4)

Alpine Above 2,500'		High (4)
Treeline 1,000'-2,500'		High (4)
Below Treeline Below 1,000'		High (4)

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

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

Happy New Year! Well, the holiday season has not disappointed. In the past week we have more than doubled our snowpack and in some areas tripled it! But, the action is not over. We will welcome in 2013 with yet another storm. This one should be quick hitting but will add another couple feet to our deepening pack.

With current snowfall rates at 1-2 inches per hour this morning we can expect all the usual storm snow problems. These are:

Wind slabs – slab avalanches formed in areas where the winds are loading slopes.
Storm slabs – slab avalanches in areas without wind that occur before the new snow has time to bond with itself.
Sluffing – loose snow avalanches on steep slopes where the new snow lacks cohesion.

The new slabs formed today will be around 1 1/2 to 2 ft deep and likely quite touchy. At elevations below 2500′ there is a crust formed by the rain on snow from Dec 30th that will act as a bed surface under the new snow. Slides triggered at these lower elevations could run quite far. Getting tangled up in one of these could quickly ruin your day. Staying out of avalanche terrain is still your best bet for getting back to the car safely.

Avalanche Problem 2

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 above concerns are all issues dealing with the storm snow and the top layers of the snowapck – but we cannot forget about what is lurking below – the unmanageable and unsurvivable deep slab problem. We continue to have a VERY WEAK foundation to our snowpack and we saw quite a bit of evidence for this yesterday. A quick break in the clouds allowed a look at the recent avalanche activity around the Pass from the past several days. Unfortunately we were not able to see all the popular haunts but HERE is a run-down of what we were able to get a peek at.

Most of the avalanches seen the past week have failed in the weak snow at the bottom of the pack. The slab on top is still around 4-6′ thick in most places and becoming more dense. The slab is also showing signs of getting harder to trigger which is setting us up for a tricky and deadly combination. Meaning, the likelihood of triggering is decreasing but if one of these pulls out, has the potential to be large and dangerous.

Weather

Tue, January 1st, 2013

We have an intense and quick hitting storm over us this morning. Several weather stations in the Turnagain Pass area are not reporting, but looking at the Girdwood Valley and Alyeska stations we are seeing ridgetop winds in the 30-40mph range (these could easily be stronger around the pass). Temperatures are beginning to cool slightly from the upper 30’s at sea level to the mid 30’s and the upper 20’s on the ridges to the mid 20’s Fahrenheit. Precipitation has begun in earnest with 10 € of snow as of 6am this morning. The rain/snow line is hovering at sea level where it should remain. We should see another 8-12 € of snow through today. Snow showers should taper off later today.

Kevin will issue the next advisory on Wednesday morning, January 2nd.

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.