Fri, November 22, 2013 Turnagain Pass Avalanche Forecast

Fri, November 22nd, 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

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

New snow that started falling Thursday afternoon built up to at least 1 foot deep at higher elevations. Snowfall amounts look fairly consistent between Girdwood and Turnagain Pass. In addition, the temperatures shot up from single digits to the mid 30s this morning. Wind peaked last night but continues to be strong this morning with gusts reaching 64mph at Sunburst. Those 2 factors – rising temperatures and wind – will make the new snow “upside down” or denser on the top than the bottom and quite a bit heavier than the underlying layer. This is a classic “unstable” setup.

Given the current snowpack, storm snow avalanches likely started happening spontaneously last night. We aren’t talking about a lot of snow yet, but it’s enough to warrant strong caution today and into the weekend. With a tapering of the snowfall this morning we won’t be seeing a lot more natural activity, but human triggered avalanches will remain a problem today.

Avalanche Problem 2

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

The ongoing wind is creating pockets of unstable snow in specific areas. Sunburst has been reading wind averaging over 20mph and gusting over 60mph since the storm began. Predominate wind direction at that site is from the East. Seattle ridge has slightly less wind from an East Southeast direction. That means West facing slopes and cross loaded North and South slopes are especially concerning.

Weather

Fri, November 22nd, 2013

With sea level temperatures currently in the mid 30s our snow has transitioned to rain in the lower elevations. It also looks like the peak of this storm has passed for eastern Turnagain Arm but ongoing snow showers will continue for the next couple days. Cooling temperatures are predicted which will transition the rain back to snow.

Freezing rain in Anchorage and at sea level this morning is expected to cause travel difficulties. Snow may become heavy at times in Anchorage this afternoon.

Schools in Girdwood and Seward are canceled today due to treacherous driving conditions! Be safe out there!

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.