Thu, November 24, 2016 Turnagain Pass Avalanche Forecast

Thu, November 24th, 2016

Alpine
Above 2,500'

Considerable (3)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Considerable (3)
Treeline 1,000'-2,500'		Moderate (2)
Below Treeline Below 1,000'		No Rating (0)

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 widespread layer of surface hoar (that formed on November 15th/16th) is buried 10-20″ below the surface and continues to be reactive. Human triggered avalanches were reported again yesterday. That makes a full week of avalanches… persistent slab avalanches. Yesterday an observer noted being able to get out onto the slab and having it break above as them well as triggering a slope that already had multiple tracks on it. They also noted that it was hard to escape the fast moving slide. These are all reasons to have your guard up, not trust the snowpack and choose your terrain wisely. In addition, folks venturing to Magnum also triggered avalanches in terrain that has not seen traffic yet this season. There are still many slopes that could potentially slide in the Turnagain Pass area. Don’t let your quest to find fresh tracks lure you into a consequential avalanche. If you do go out today pay attention to the surface conditions. What will be buried by new snow? There is a new layer of surface hoar forming and the surface snow is also being weakened(faceting) due to the colder temperatures.

Again, things to keep in mind for the sunny day forecast:

The snowpack is still unstable, remote triggering is possible. Be on the lookout for shooting cracks.

The larger and more connected the slope is, the larger the avalanche = higher consequences
Slabs can break above you, making it more difficult to escape
Be aware of OTHER groups and WHO IS BELOW YOU

Here is a little more information on Persistent Slabs and Travel Advice. This comes from the Utah Avalanche Center’s Avalanche Problem Toolbox, authors: Drew Hardesty and Wendy Wagner!

Skier triggered slide yesterday on Sunburst. Slope had previous tracks on it. Photo: Mike Records

Avalanche Problem 2

Glide Avalanches

Glide Avalanches

Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

More info at Avalanche.org

There were two glide avalanches reported in the past two days and glide cracks are visible in the other pieces of terrain. Give these wide berth, minimize time spent underneath glide cracks and remember these are totally unpredicatable. They are not triggered by humans and are the entire snowpack releasing.

Sunburst glide avalanche and glide crack. This released sometime between Tuesday afternoon and Wednesday morning. Photo: David Evans

Weather

Thu, November 24th, 2016

Yesterday was a clear sunny day in the mountains. Winds were light and temperatures were in the mid 20Fs. Overnight the temperatures dipped into the teens in valleys and winds remained light and variable.

Today will be similar with clear skies and temperatures in the 20Fs. WInds will pick up to 10-20mph from the NW. There will be increasing clouds overnight and a chance of snow showers.

Tomorrow will be mostly cloudy with snow showers, 0-3″ possible. This system is forecasted to linger and bring snow to the region into next week.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	24	0	0	18
Summit Lake (1400′)	14	0	0	2
Alyeska Mid (1700′)	27	0	0	2

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	24	variable	3	12
Seattle Ridge (2400′)	26	variable	3	9

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/18/21	Turnagain	Observation: Tincan Ridge	Joe Kurtak
04/30/21	Turnagain	Observation: Sunburst	W Wagner Forecaster
04/27/21	Turnagain	Observation: Tincan Ridge	Joe Kurtak
04/26/21	Turnagain	Observation: Magnum	Creighton/ Hoople
04/25/21	Turnagain	Observation: Sunburst	Nick D'Alessio
04/24/21	Turnagain	Observation: Airplane obs	Johnston-Bloom / DiJulia /Hilliard Forecaster
04/24/21	Turnagain	Observation: Corn biscuit	Heather Johnson
04/23/21	Turnagain	Avalanche: Lynx Ck Drainage	W Wagner Forecaster
04/23/21	Turnagain	Avalanche: Sunburst	Eeva Latosuo
04/23/21	Turnagain	Observation: Center Ridge Turnagain pass	Joe Kurtak

Riding Areas

Updated Tue, June 01st, 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	Closed
Placer River	Closed	It is packrafting and jetboat season!
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	Closed	Closed as of June 1. 188 day season, that\'s a wrap!
Twentymile	Closed	It is packrafting and jetboat season!
Seward District
Carter Lake	Closed	Closes May 1.
Lost Lake Trail	Closed	Closes May 1.
Primrose Trail	Closed	Closes May 1.
Resurrection Pass Trail	Closed	Closed for the 2020/21 winter season. Will be open for moto use in the 21/22\\\' winter season as per the CNF Forest plan.
Snug Harbor	Closed	Closes May 16th.
South Fork Snow River Corridor	Closed	Closes May 1.
Summit Lake	Closed	Closes May 1.