Fri, March 27, 2015 Turnagain Pass Avalanche Forecast

Fri, March 27th, 2015

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Moderate (2)
Below Treeline Below 1,000'		No Rating (0)

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

Yesterday 1-2′ of new snow fell in Alpine of Gridwood and Turnagain Pass and the most intense part of this storm occurred between 2am and Noon. Ridgetop winds averaged in the mid 20’s mph from the Northeast with gusts into the high 40’s mph for a 24 hour period.

Storm snow totals are from the last 36 hours:

Turnagin Pass ≈ 1” of water (16” at 2800’)

Girdwood = 2.05” of water (21” at 2800’ at Alyeska)

Summit Lake ≈ 0.1 water (trace)

This new snow will likely gain strength quickly as it settles, but triggering a wind slab up to 2’ thick is possible on steep slopes. Surface conditions below this new snow are variable with a sun crust on Southern and Eastern aspects and pockets of weaker snow on Northern and Western slopes. Today it will be important to avoid large steep sustained slopes and give this new snow a chance to adjust to the variable bed surfaces below.

Moderate ridgetop winds yesterday were transporting snow in the Alpine. Photo taken at 3200′ on the ridgeline above Common Bowl,Tincan

Avalanche Problem 2

Wet Loose

Wet Loose

Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

More info at Avalanche.org

Yesterday several loose snow ‘point releases’ and a small storm slabs were observed in steep terrain in Turnagain Pass. This new snow will be susceptible to rapid warming due to solar affect and could cause wet point releases and wet slabs if the sun makes an appearance. It will be important to monitor the sun’s affect today – even thin cloud cover could increase solar affect acting as a large reflector. Pay attention for moist surface conditions and avoid large steep slopes that will have more volume if an avalanche is triggered.

Small D1 point releases “sluffs” and a fresh storm slab on “CFR” on Tincan mid day during a brief window of good visibility.

Day-time temperatures yesterday were warm and rain/snow line moved from 800’ in the morning to 1700’ in the afternoon. This caused a period of rapid melting below this elevation. Today wet loose avalanches on steep terrain features will be an additional hazard below treeline. 8-10” of heavy wet snow could be challenging to move through and early season conditions like open drainages and tree wells exist at this lower elevation band. Avoid terrain traps – it could be difficult to dig yourself out if caught up side down.

Two photos taken yesterday of the same tree at 1600′.1st picture was taken at 11:30am and the second was taken at 4pm after rain/snow line moved to 1700′. Photo by John Fitzgerald.

Weather

Fri, March 27th, 2015

Total precipitation for Turnagain Pass was near an inch of water, which was a mix of rain and snow depending on elevation. Rain/snow line was at 800′ yesterday morning, but quickly moved to 1700′ by the afternoon. Temperatures at sea level were in the mid 30’s F to low 40’s F, and upper 20’s F at ridgetops. Ridgetop winds averaged in the 20’s mph with gusts into the high 40’s mph from the NE.

Today rain and snow showers are expected and patches of sun are possible. Rain/snow line will likely be near 2000′ today and up to 3 € could fall at higher elevations. Temperatures will remain warm; high 30’s F at sea level and mid 20’s F along ridgetops. Ridgetop winds will be from the East, 10-20 mph.

A low pressure system South of the Alaska Peninsula will bring another burst of rain and snow to Southcentral Alaska over the weekend. This will continue to bring us warm moist air, rain near sea level and snow in the interior and in the Alpine. It is uncertain how much precip will fall. Winds will likely be moderate at times, 20-30 mph from the East along ridgetops.

*Seattle Ridge Wx Station is not producing accurate wind direction data at this time.

PRECIPITATION 24-hour data (6am – 6am)

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	34	5	0.4	60
Summit Lake (1400′)	36	1	0.1	12
Alyeska Mid (1700′)	34	1	0.89	32

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	26	ENE	23	49
Seattle Ridge (2400′)	28	*	19	41

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.