Mon, March 04, 2013 Turnagain Pass Avalanche Forecast

Mon, March 4th, 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

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

While it has been several days since any significant snowfall has accumulated, recent ridgetop winds have been high enough to blow snow around and create fresh wind slabs. Expect to encounter these slabs in upper elevation starting zones. Be on the lookout for snow that feels hollow or looks smooth and pillowy. These slabs will be confined to smaller pockets but will be up to a foot in depth.

Additional Concerns

Cornices
Warm temperatures and sunshine helped to release several cornices in the forecast area on Saturday. While cloud cover will help to lower the likelihood of natural cornice releases today, warm temps and recent winds will conspire to make this a real problem in the mountains today. A cornice triggered avalanche that occurred on Magnum on Saturday is a prime example of why it is important to know what is above you when traveling up a valley.

Loose Snow avalanches
Wet loose snow will be moving under the influence of a person’s weight today. Avoiding steep terrain as the snow surface becomes more damp will be the best way to avoid this problem. This problem will be more pronounced in the lower elevations.

Avalanche Problem 2

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

A weak layer of snow sitting on a crust at the mid elevations (1,500′-3,000′) continues to be a concern. This weak layer/crust combo is buried 2-6 feet deep and has shown to be less of a problem on Turnagain Pass but more pronounced in outlying areas such as Summit Lake and the Girdwood, 20 Mile and Placer Valleys. With rising temperatures this interface is more of a concern, as it will become easier for a person or snowmachine to affect these deeper layers. As with all of the concerns today, pay attention to the thermometer and back off steep terrain as things warm up.

Weather

Mon, March 4th, 2013

The mountains around Eastern Turnagain Arm have picked up just a trace to 1″ of new snow in the past 24 hours. Temperatures have been mild, with high 30s F at sea level, mid 20s F at 2,400′, and low 20s F at 3,800′. The Seattle Ridge weather station has been reporting winds averaging in the mid to high 20 mph range out of the SE with gusts to 46.

Today expect mostly cloudy skies and temperatures warming to 37 degrees F at 1,000′. Winds will be out of the SE at 5-15 mph with gusts to 20 mph. Snowfall amounts will be very light.

The extended outlook calls for continued mild temperatures and a mix of sun and clouds for the next several days.

____________________________________________________________________

Wendy will issue the next advisory tomorrow morning, March 5th.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
02/07/23	Turnagain	Observation: Seattle Ridge	Wagner / Keeler Forecaster
02/07/23	Turnagain	Avalanche: Pete’s North	Megan Guinn
02/05/23	Turnagain	Observation: Rookie Hill	Tony Naciuk
01/31/23	Turnagain	Observation: Johnson Pass area	Megan Guinn / W Wagner Forecaster
01/29/23	Turnagain	Observation: Tincan Backdoor	AAS-Level 1 1/27-1/30
01/28/23	Turnagain	Observation: Sunburst	Brooke Edwards
01/28/23	Turnagain	Avalanche: Seattle Ridge	W Wagner
01/28/23	Turnagain	Observation: Tincan Common	Tony Naciuk
01/27/23	Turnagain	Observation: Sunburst	John Sykes
01/27/23	Turnagain	Avalanche: Lynx Creek	Megan Guinn / W Wagner

Riding Areas

Updated Fri, January 06th, 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	Open	Opened Dec 13th.
Placer River	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Skookum Drainage	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Turnagain Pass	Open	Opened Dec 13th.
Twentymile	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Seward District
Carter Lake	Open	Opened Dec 13th.
Lost Lake Trail	Open	Opened Dec 13th.
Primrose Trail	Open	Opened Dec 13th.
Resurrection Pass Trail	Closed	Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor	Open	Opened Dec 13th.
South Fork Snow River Corridor	Open	Opened Dec 13th.
Summit Lake	Open	Opened Dec 13th.