Sun, January 18, 2015 Turnagain Pass Avalanche Forecast

Sun, January 18th, 2015

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Low (1)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Low (1)
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

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

Lingering wind slabs formed during last Wednesday and Thursday’s storm, along with continued strong Easterly winds on Friday, will be the primary avalanche problem in the backcountry. These slabs are roughly 1-2′ thick and composed of hard/dense snow. They are confined to elevations above 3,000′ just off ridgelines and in other catchment zones such as cross-loaded gullies. With a dusting of 1-3″ of low density snow in the past day and a half, they are likely to be somewhat obscured. They are also likely to be quite stubborn and hard to trigger and will most likely take slope angles approaching 40 degrees or steeper to get them to pop out.

If you find yourself venturing into high elevation more extreme terrain, remember your safe travel techniques – mainly exposing one person at a time on a slope. These slabs are hard so pole tests may not tell you much. Also, other red flags such as shooting cracks and hollow feeling snow may not be present until it’s too late.

Photo below: Winter has returned, for the time being, above 2,500′ – a welcome sight!!

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

Although glide activity appears to be slowing down in the region, cracks are likely still opening and the possibility remains for these to avalanche. The most recent glide avalanche is suspected to be in the past 48 hours. This was in upper Lyon Creek on a West aspect (photo below, taken looking East from Tincan). Most of the activity we have seen has been in the 2,500-3,000’ elevation band and on all aspects. Glide avalanches are unpredictable and are best managed through avoidance, as they can release at anytime. If you are traveling along valley bottoms watch for cracks above and limit your exposure when passing below them.

Most recent suspected glide avalanche in the Turnagain Pass region below:

Weather

Sun, January 18th, 2015

A welcome 2″ or so of new snow fell yesterday during the early morning hours above 1,500′, which was followed by gradually clearing skies and light Easterly winds. Overnight, we have seen an additional trace of new snow down to 1,000′ on Turnagain Pass. Ridgetop winds have remained light from the East while temperatures have stayed cool, mid 20’sF on the ridgelines and 32F at 1,000′.

Today, we can expect intermittent cloud cover and snow showers throughout the Eastern Turnagain Arm zone with the rain/snow line hovering just above sea level. Snow accumulations are expected to be small, around 1″. Ridgetop winds should be light and variable and temperatures look to stay in the mid 20’s F on Ridgetops and around 34F at 1,000′.

For Monday, we should see the cooler air, light variable winds and partly cloudy skies continue with little to no precipitation. Our next shot at precipitation looks to be Wednesday. Stay tuned.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	30	1	0.1	30
Summit Lake (1400′)	29	3	0.2	8
Alyeska Mid (1700′)	32	1.5	0.14	18.5

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	24	E	7	19
Seattle Ridge (2400′)	27	N/A: Wind	sensor	is rimed

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.