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
05/21/22	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
04/24/22	Turnagain	Avalanche: Seattle Ridge – large glide avalanche on Repeat Offender path	CNFAIC Staff Forecaster

Riding Areas

Updated Fri, May 13th, 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	Open	Open. Extended opening through May 31.
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.