Fri, February 15, 2013 Turnagain Pass Avalanche Forecast

Fri, February 15th, 2013

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

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

Intense snowfall combined with strong winds in the early part of the day yesterday have created new slabs 2-3′ in depth. Expect these slabs to be sensitive to the weight of a person or snowmachine today. While some time has allowed the underlying snow to adjust to this new load, there is enough new snow, especially in wind loaded terrain to warrant concern. These slabs are large enough on their own to injure or bury a person. At the mid elevations, there is the possibility of these slabs to step down to older layers of weak snow. Be on the lookout for shooting cracks, collapsing/whoompfing and snow that has a hollow feel to it. Staying off of steep rollovers, starting zones and snow that has a rounded or pillowy look will help in avoiding this problem today.

Avalanche Problem 2

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

Snowfall amounts ranged from a few inches at lower elevations to 16″ in the higher elevations in the past 24 hours. Expect these slabs to gradually become less reactive as the day progresses. These instabilities tend to heal quickly. However, an additional 4 inches of snow today will keep this problem lingering through the day. Expect storm snow to release in terrain over 35 degrees as we experienced yesterday. This problem will be more apparent and pronounced as you gain in elevation, particularly where new snow amounts exceed 10″.

Additional Concerns
Persistent Slabs

A crust that formed in the latter part of January has shown up as a problem in certain areas in our region in the past week. A thin layer of weak snow between this crust and 2-3 feet of snow is the interface that concerns us most. This crust is most pronounced between 1,800-2,400′. This problem is not as geographically widespread as our primary concerns. When traveling within this elevation band today steer away from slopes over 35 degrees, as avalanches in the new snow have the potential to step down to these older layers of weak snow.

Cornices

Cornices have significantly gained in mass over the last 24 hours. Keep your distance from cornices today. They will likely be sensitive to the weight of a person or snowmachine.

Weather

Fri, February 15th, 2013

The mountains around Turnagain Arm have picked up 16″ inches of snow with 1″ of water in the higher elevations over the past 24 hours. Winds averaged 30mph out of the East in the morning yesterday and temps were moderate, averaging in the low 20s at 3,800′. Snowfall was most intense during the late morning/early afternoon yesterday.

Lingering snow showers are continuing to put down light amounts of snow around the area. Winds calmed down in the afternoon yesterday and are currently averaging 2mph out of the West at the Sunburst weather station. Temps are currently 20 degrees F at ridgetops and around 32 F at sea level.

Today lingering snow showers should produce up to 2-4 inches of accumulation. Ridgetop winds will blow out of the West at 5-20mph and temperatures at 1,000 feet will be in the high 20s.

Tomorrow we should see clearing skies as a small ridge between low pressure systems moves through the area.

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Wendy will issue the next advisory tomorrow morning, February 16th.

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.