Mon, November 27, 2017 Turnagain Pass Avalanche Forecast

Mon, November 27th, 2017

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

Moderate (2)

Alpine Above 2,500'		Moderate (2)
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

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

Normally, an article warning Alaska drivers of winter weather road condtions would be business as usual, but for those of us looking to recreate at or around Turnagain Pass, an area that has seen cold and dry conditions for November, it means it is FINALLY snowing. Temperatures have warmed, winds have increased and snow is falling. The storm is coming from the East, hitting Portage Valley with several inches of snow at sea level overnight. Girdwood Valley has seen 4-6″ of snow at the mid to upper elevations. Turnagain Pass looks to be un-favored with a mear 1-2″ so far.

Light snowfall should continue today with an evening total of 6-8″ at the upper elevations in Girdwood Valley and 3-5″ at Turnagain Pass. The Summit Lake area may squeeze an inch or two, but this system looks to be favoring Portage Valley and North.

AVALANCHE CONDITIONS:

The excitement is building and powder fever is setting in. Please remember, not only is it early season, with plenty of rocks and alders to get caught in, we are also expecting increasing avalanche danger as well.

What to watch for:
1 – How much new snow has fallen?
2 – Has the wind blown, or blowing?
3 – Are there fresh wind slabs that crack at your feet? Stiffer snow over weaker snow?

Today’s equation is relatively simple. New snow + wind = wind slabs. If you find an area that has seen enough new snow for a wind slab, it is likely to be triggered easily on the steeper slopes (such as 35 degrees or steeper). Turnagain Pass is still VERY thin and may only see a couple inches of new snow – in this case avalanches are not expected. In the Portage and Girdwood Valleys, there looks to be enough snow to form shallow wind slabs.

As we head into this week, the main concern is weak faceted snow that will be covered up in the next few days. See Heather’s video below. Other slopes are covered with hard crusts and hard wind drifts. The weak faceted snow is our greatest concern for future snow load as it will likely inhibit the new snow from bonding. More to come on this during the week.

A look at the ridgeline conditions before snowfall:

Weather

Mon, November 27th, 2017

Temperatures have warmed (relatively, to the 20’s and 30F), winds have increased from the East (Moderately, to the 15-25 mph) and snow is falling. The storm is coming from the East, hitting Whittier and spilling over into the Portage Valley with several inches of snow at sea level overnight. Girdwood Valley has seen similar, yet with 4-6″ of snow at the mid to upper elevations. Turnagain Pass weather stations are reporting a mear 1-2″ so far.

Light snowfall should continue through most of the day and begin to tapper off this afternoon/evening. A total of 6-8″ is expected at the upper elevations in Girdwood Valley and 3-5″ at Turnagain Pass. The Summit Lake area may squeeze an inch or two, but this system looks to be favoring Portage Valley and North.

After this system passes, another yet stronger low pressure moves in Monday night. And another one after that. Here are the National Weather Station ‘icons’ for the grid point over Turnagian pass:

PRECIPITATION 24-hour data (6am – 6am)

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	26	1″	0.1″	7″
Summit Lake (1400′)	15	0	0	7″
Alyeska Mid (1700′)	20	4.5″	0.3″	11″

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	19	E	11	52
Seattle Ridge (2400′)	22	Sensor Rimed	Sensor Rimed	Sensor Rimed

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 Thu, June 01st, 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	Closed May 15.
Placer River	Closed	Closed May 15.
Skookum Drainage	Closed	Will close to motorized use on April 1, 2023 per the National Forest Plan.
Turnagain Pass	Closed	Will close on June 1.
Twentymile	Closed	Scheduled closure May 1.
Seward District
Carter Lake	Closed	Scheduled closure May 1.
Lost Lake Trail	Closed	Scheduled closure May 1.
Primrose Trail	Closed	Scheduled closure May 1.
Resurrection Pass Trail	Closed	Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor	Closed	Extended opening until May 15.
South Fork Snow River Corridor	Closed	Scheduled closure May 1.
Summit Lake	Closed	Scheduled closure May 1.