Sun, January 10, 2016 Turnagain Pass Avalanche Forecast

Sun, January 10th, 2016

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

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

In Turnagain Pass storm snow instabilities due to recent snow, rain and active wind loading are today’s primary concerns.

Wind Slabs – Today Easterly ridgetop winds are expected to be in the 30-40’s mph for the second day in a row with an additional 3-5” of new snow. This means avalanches will be composed of the new storm snow from the last two days and are not expected to break into layers deeper in the pack. Isolated windslabs 1-2’ deep are possible on windloaded features. This problem is manageable by avoiding slope angles over 35° where the snow is windloaded. Pay attention for stiff hollow snow, shooting cracks, and snow being transported off of ridge tops.

Wet Loose – A saturated snow pack was observed yesterday below 1500’ causing the snow to be loose and unconsolidated. This problem is stabilizing in places where temperatures cooled enough to form a crust. Should you encounter wet saturated snow, this is an additional reason to avoid gullies and steep channeled terrain. This problem is more developed in Girdwood where more over an 1″ of rain saturated the snowpack yesterday at lower elelvations.

Should a break in the weather today allow for easier travel remember to practice safe travel rituals.

Only expose one person at time on a slope
Regroup in safe zones
Always have an escape route

Yesterday two very small natural windslabs were observerd on Southeast aspects near Johnson Pass. These crossloaded gully features are examples of terrain that could harbor tender windslabs today.

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

Glide cracks have been appearing throughout Turnagain Pass over the last week. Warm temperatures and rain have been adding stress to these very unpredictable hazards. Pay attention for large open cracks in the snow, ‘crevasse looking’ features that can release without any warning. Similar to managing a cornice, it is best to avoid traveling on or under slopes with glide cracks.

Additional Concern

Cornice

Cornice

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.

More info at Avalanche.org

Cornice features have grown large over the last few weeks, and todays blowing snow may be adding stress to their unstable nature. They have the potential to fall naturally or be triggered by the weight of a person or machine and can be very dangerous. Travel under or on them should be avoided. They have the tendency to break farther back from the ridge than expected. As you approach ridgelines, ensure you aren’t accidently traveling on overhanging snow.

Weather

Sun, January 10th, 2016

Yesterday 36F temps caused rain along Turnagain Pass (1000′), and by afternoon temps cooled to 32F with scatted snow showers in the afternoon. 4-8″ of new snow fell in the upper elevations. Rain/snow line was estimated to have reached 2000′ early yesterday morning. Easterly Ridgetop winds averaged in the 30’s mph with gusts in the 60’s mph.

Today Easterly ridgetop winds are expected to average in the 30-40’s mph. Gust could reach into the 60’s mph. Up to 5 € of snow is expected above 1100′ today and light rain at lower elevations. Temperature should hover around freezing 32F along road level at Turngain Pass.

Expect warm temperatures, snow and rain to continue through mid-week.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	31	4	0.4	85
Summit Lake (1400′)	33	1	0.1	25
Alyeska Mid (1700′)	32	10	1.22	66

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	23	ENE	28	64
Seattle Ridge (2400′)	28	n/a	n/a	n/a

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
12/10/19	Turnagain	Avalanche: Tincan and Sunburst from the air	CNFAIC Staff
12/10/19	Turnagain	Observation: Tincan	Nancy Pfeiffer
12/08/19	Turnagain	Avalanche: Tincan	Ryan Van Luit Forecaster
12/06/19	Turnagain	Avalanche: Sunburst	Billy Finley
12/04/19	Turnagain	Observation: Sunburst	A.Johnston-Bloom/ W.Wagner/ R.Van Luit Forecaster
12/03/19	Turnagain	Observation: Hippy Bowl	Nick Langowski
12/01/19	Turnagain	Observation: Tincan, All elevations	Eric Roberts
12/01/19	Turnagain	Observation: Tincan	Andy Moderow
11/30/19	Turnagain	Observation: Tincan Treeline Plateau/ Common Bowl/ Ridge	Eric Roberts
11/29/19	Turnagain	Observation: Sunburst Ob #2	Aleph Johnston-Bloom Forecaster

Riding Areas

Updated Wed, December 11th, 2019

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.
Placer River	Closed	Closed.
Skookum Drainage	Closed	Closed.
Turnagain Pass	Closed	Closed.
Twentymile	Closed	Closed.
Seward District
Carter Lake	Closed	Closed.
Lost Lake Trail	Closed	Closed.
Primrose Trail	Closed	Closed.
Resurrection Pass Trail	Closed	Closed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor	Closed	Closed.
South Fork Snow River Corridor	Closed	Closed.
Summit Lake	Closed	Closed.