Sat, March 02, 2013 Turnagain Pass Avalanche Forecast

Sat, March 2nd, 2013

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

Dry Loose

Dry Loose

Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

More info at Avalanche.org

Today watch for steep sunlit slopes to be the most likely place to trigger a loose snow avalanche. Expect sluffs to become wet and increase in volume with the presence of sunshine and higher temps. Yesterday my partner and I observed several natural loose snow avalanches in terrain over 40 degrees and we were able to initiate sluffs in this terrain as well. Expect similar activity today and make sure that you are aware of the terrain below you. If you see loose snow moving downhill with you or in front of you steer away from it at a gradual angle before it knocks you over. Getting knocked down by these avalanches will have greater consequences when a person is above terrain traps such as cliffbands, gullies, or trees.

Additional Concerns

Wind Slabs
Winds have been generally light over the past 24 hours. There was a 4 hour window last night where Easterly winds increased enough to create new shallow wind slabs. Older wind slabs formed during the past week are less likely to be an issue today. Nonetheless, it is worth avoiding steep terrain where the combination of loose snow and isolated pockets of wind slab will be enough to knock you off of your feet or snowmachine.

Cornices

Sun and warming will increase the chances of cornices breaking and dropping onto slopes today. Give cornices a wide berth from below and above, as they can do a lot of damage to a person.

Avalanche Problem 2

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

The storms of the past week have put down 2-3 feet of “new” snow that is sitting on a crust. In some areas weak snow sits on top of this crust that exists between ~1,500-3,000′. Snowpit tests yesterday did not show this interface to be a serious concern on Turnagain Pass. That could change today, as warm temperatures and sunshine will make it easier to trigger deeper avalanches on steep lower elevation slopes, and areas where the newest slab is thinner. Areas with less overall snow (e.g. heading south towards Summit Lake and lower elevations in general) are where it is worth paying more attention to this problem today.

Weather

Sat, March 2nd, 2013

The mountains around Eastern Turnagain Arm have picked up 2″ of new snow containing .1″ of water in the past 24 hours. Winds have been generally light out of the E and SE averaging 8mph with gusts as high as 36mph. Temperatures at 3,800′ have averaged 18 degrees F and 25 degrees at 1,880′.

Today expect a mild and calm day in the mountains. Sunshine and warm temps will be the most important weather factors today in terms of avalanche activity. Expect periods of clear skies and temperatures to be in the high 30s at 1,000′. Ridgetop winds will be light, coming out of the SE at 5-10mph.

The extended outlook calls for a mix of sun and clouds over the next several days with only a slight chance of snow.

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Wendy will issue the next advisory tomorrow morning, March 3rd.

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.