Sat, February 15, 2014 Turnagain Pass Avalanche Forecast

Sat, February 15th, 2014

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

Snowfall amounts over the past 24 hours ranging from 6” in the lower elevations to 18” in the higher elevations are bringing with it all of the issues related to storm snow.

Loose Snow avalanches
Yesterday my partner and I were able to easily produce sluffing in steep terrain, generally over 40 degrees. Loose snow sluffs will be easy to trigger today and could entrain enough snow to knock people off of their feet. This issue becomes exacerbated when traveling above terrain traps such as cliffs, trees, and gullies.

Storm Slabs
Enough snow has fallen over the past 24 hours to create slabs without the presence of wind. While the general set up on the surface is loose snow, slabs were beginning to form in sheltered areas late in the day yesterday. Be on the lookout for shooting cracks when traveling on terrain 35 degrees and above today. While these slabs are generally soft, the potential exists for them to propagate across slopes and run far.

Wind slabs
Winds out of the East cranked up enough yesterday afternoon and into the night to create wind slabs up to 2 feet in depth that will be very sensitive to the weight of a person today. Avoiding leeward slopes above 35 degrees is your best bet for avoiding this problem. These newly formed slabs also have the potential to trigger deeper layers in the snowpack.

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 most prominent weak layer above 3,500’ is facets sitting on the stout January crust. This layer (along with the crust) has been associated with remotely triggered avalanches over the last week. Since Feb 7th, up to 30” of snow with 2” of water has fallen in the higher elevations. This slab has had time to settle and become more dense. The interface between this slab and the January crust is suspect. Visibility yesterday limited our ability to assess this interface. Because of this lack of information, this layer & the slab above it are guilty until proven innocent. Avoidance of steep (over 35 degree) upper elevation starting zones and cross loaded gullies will be the best management tactic related to this problem today.

Weather

Sat, February 15th, 2014

Winter Part 2 has arrived!

In the past 24 hours the Turnagain Pass SNOTEL site has picked up 14 € of new snow with 1 € of water. The Girdwood Valley has seen less amounts, with stations averaging 6-8 € snow with .5 € of water. Winds that picked up overnight have calmed this morning. Sunburst averaged 20mph with gust to 69mph. Ridge top temps have averaged in the low teens and are currently reading in the high single digits F.

Today expect a continuation of light snowfall. Accumulations of 2-4 € are possible. Temperatures at 1,000′ will be in the teens to low 20s F. Winds will be out of the East at 10-15 mph.

A very large area of Low pressure centered over Kodiak island will remain in place through the weekend. Expect light snow with occasional breaks in the clouds to continue through the next several days.

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.