Sun, February 24, 2013 Turnagain Pass Avalanche Forecast

Sun, February 24th, 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

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

Today’s main player in the avalanche game will be the wind. Yesterday’s new snow came in with strong east wind and though the wind died down overnight, it is forecast to pick back up today. Both lingering slabs formed yesterday, as well as fresh slabs today, will be the thing to watch out for. With the addition of a few inches of snow today, expect these slabs to be in the 8-16″ range. Keeping an eye out for active wind loading and cracking in the snow around you will be your best clue to finding and avoiding a wind slab.

Additional Concerns:

Loose snow avalanches: In areas without wind effect, kicking off sluffs on the steeper slopes should be expected. These are not likely to be large due to the modest amounts of new snow.

We received a bit of a refresher yesterday. 4-8” of new snow not only covered the upper elevations but made its way down to sea level as well. Below treeline riding conditions are drastically improving from a week ago and now harbor a few wind slab and loose snow avalanche concerns as well.

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 outlier. There are two layers buried below the surface that are worth mentioning: (1) facets above the late January crusts 3-6’ deep and (2) weak early season snow near the ground. Triggering one of these layers is most pronounced in areas with a shallow snowpack (i.e., the interior Kenai Mountains as well as thin slopes in the Turnagain/Girdwood zones). Keeping with safe travel practices and steering clear of thin areas are your best bet for avoiding one of these outliers.

Weather

Sun, February 24th, 2013

Yesterday’s modest storm brought snow to sea level and varying amounts to the region. The north side of Turnagain Pass through Girdwood picked up roughly 4-8 € while the east side of the Pass was about half that. Summit Lake looks to have seen 2-3 €. Winds associated were easterly averaging 20-30mph with gusts to the 50’s. Temperature was in the mid-teens at ridgetops and around 30F at sea level.

A brief break between systems overnight will be short lived as a weak front will bring a few more inches of snow and moderate east wind this afternoon. Temperatures are expected to remain in the mid-teens on ridgetops and near 30F at sea level

Lately, several of the low pressure systems that have been passing by have been far enough to the south to keep the warm air at bay and snow at sea level. This trend is expected to continue for several more days – good news for the lower elevations.

Fitz will issue the next advisory tomorrow morning, February 25^th.

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.