Sun, December 22, 2013 Turnagain Pass Avalanche Forecast

Sun, December 22nd, 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

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

We had no reports of avalanche activity yesterday, however the visibility was poor and it looked as though most folks were staying in the trees and out of steep avalanche terrain.

Another small shot of precipitation has added 3-5″ of dense snow to our snowpack since Friday night and we have another 1-2″ possible for today. The new snow is sticking rather well to the surface but it’s the weak snow buried 12-16″ down that we are worried about. This new snow is not likely to be enough to overwhelm the buried weak layers but the added weight of a person could be. In fact, we know a person can overwhelm these weak layers by the widespread collapsing that continues at all aspects and elevations in the mountains. For a closer look at our weak foundation click this link and check out the video and see this report from the north side of the Pass.

For today, sticking to lower angle terrain, without steeper slopes above you, will be your best bet at avoiding a potential avalanche.

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

Though the snow is heavy and wet at the parking lots on Turnagain Pass, it is dry at the upper elevations and able to be transported by the wind. Winds are forecast to shift and start bumping up from the Northwest by noon today and fresh wind slabs may start forming above treeline. This flow direction is prime for loading the Southeast face of Seattle Ridge – the slopes right above the motorized parking lot. By tonight the Northwest flow may reach over 50mph averages, so keep your eyes peeled in case the wind is ahead of schedule.

*Fresh wind slabs will have the potential to overload the weak snow deeper in the pack and larger and more dangerous avalanches could be triggered. Steer well away from any area with fresh wind deposited snow.

Weather

Sun, December 22nd, 2013

Yesterday we had light snowfall which turned to rain at sea level in the afternoon. We picked up around 3″ of heavy wet snow above 500′. Rain snow line was around 200′. Temperatures were in the mid 20’s at the ridgetop stations and low 30’s at sea level. Winds were blowing 10mph with gusts to 30mph from the East during the day and have dropped to ~5mph overnight.

During the past 36 hours precipitation totals: 3-5″ of heavy wet snow (.3-.6 water equivalent).

It will start out as another soggy day today but cool down by this afternoon as the warm area of low pressure over us moves off to the East. We might pick up 1-2″ of snow as this system exits. Winds should shift to the North by mid-morning and increase to the 15-20mph range. With this we should see the temperature drop to the teens on the ridges and mid 20’s at sea level.

On Monday skies should clear up and temperatures continue to drop back to the single digit range with the North flow. Another system looks to brush by us on Christmas Eve and Christmas.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/06/20	Turnagain	Avalanche: Pastoral Peak, north face	Andy Duenow
04/10/20	Turnagain	Avalanche: Wolverine	Mike Records
04/10/20	Turnagain	Observation: Eddies lookers right shoulder	Matt Yoder
04/09/20	Turnagain	Observation: Bench Peak	Mike Records
04/04/20	Turnagain	Observation: Tincan	Anonymous
04/04/20	Turnagain	Observation: Pete’s North	Anonymous
03/26/20	Turnagain	Avalanche: Tincan – Proper (SW facing)	CNFAIC Staff
03/26/20	Turnagain	Avalanche: Seattle Ridge	W Wagner Forecaster
03/25/20	Turnagain	Avalanche: Sunburst Uptrack @ 2000′	J. Boisvert
03/24/20	Turnagain	Observation: Turnagain – Road Observations	W Wagner Forecaster

Riding Areas

Updated Mon, October 26th, 2020

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
Placer River	Closed
Skookum Drainage	Closed
Turnagain Pass	Closed
Twentymile	Closed
Seward District
Carter Lake	Closed
Lost Lake Trail	Closed
Primrose Trail	Closed
Resurrection Pass Trail	Closed
Snug Harbor	Closed
South Fork Snow River Corridor	Closed
Summit Lake	Closed