Wed, February 24, 2016 Turnagain Pass Avalanche Forecast

Wed, February 24th, 2016

Alpine
Above 2,500'

High (4)

Treeline
1,000'-2,500'

High (4)

Below Treeline
Below 1,000'

Moderate (2)

Alpine Above 2,500'		High (4)
Treeline 1,000'-2,500'		High (4)
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

The snowpack was just starting to adjust to the ‘mini-snowpocalypse’ over the weekend and now we are back into an active loading scenario. Overnight we received over a foot of snow and sustained strong winds in the Alpine. Sunburst recorded a peak gust of 105 at 2 am. There is a lot of snow available for transport and snow is forecasted to fall thoughout the day. The NWS service used the phrase heavy at times to describe snowfall rates. Deep wind and storm slabs and large cornices may release naturally as the storm continues today. These will no doubt be very sensitive to human triggers. Visibility will be limited; strong winds will continue and rain is forecasted to fall on the fresh snow in the mid-elevation band up to approximately 1800′.

Today we are again saying travel in or under avalanche terrain is not recommended. Please be patient.

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

As the temperature rises and with it the rain/snow line, rain will be falling on new snow. There is the potential for wet loose avalanches in steep terrain in the mid-elevation band. We may see wet slab activity as well due to the stiff crust under this last shot of snow. Wet avalanches are yet another reason to avoid travel in or under avalanche terrain today.

Additional Concern

Glide Avalanches

Glide Avalanches

Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

More info at Avalanche.org

Underneath all the new snow glides are still lurking and have the potential to release at any time. Glides threaten a lot of well-travelled terrain on both the motorized and non-motorized side of the highway. Still looking for a reason to avoid avalanche terrain and runout zones today??? Here is one more avalanche dragon to steer clear of.

Weather

Wed, February 24th, 2016

Yesterday was cloudy and visibility was limited. Snow fell throughout the day with over a foot of accumulation overnight. Winds ramped up in the evening blowing in 50-60 mph with a peak gust of 105. Temperatures were in the 20Fs. Rain/snowline was around 300′.

Today will be mostly cloudy and snow and rain are forecasted to be heavy at times with another inch of moisture expected today and another 1.5 inches tonight. These means a total of 15-30 inches of snow at higher elevations is possible. Winds will be Easterly, 25-50 mph and temperatures will be in the mid to high 30Fs. Rain/snow line is expected to rise to 1800′.

There may be a minor lull in this active weather during the day Thursday with some lingering showers. Another system is forecasted to move in Thursday evening or Friday morning.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	30	14	1.5	134
Summit Lake (1400′)	32	4	.4	45
Alyeska Mid (1700′)	31	9	1	105

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	22	ENE	45	105
Seattle Ridge (2400′)	25	n/a	n/a	n/a

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 Sat, September 23rd, 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	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Placer River	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Skookum Drainage	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Turnagain Pass	Closed	Scheduled opening on the Wednesday before Thanksgiving per Chugach National Forest plan. Subject to adequate snow cover.
Twentymile	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Seward District
Carter Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Lost Lake Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Primrose Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Resurrection Pass Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Snug Harbor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
South Fork Snow River Corridor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Summit Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.