Mon, February 03, 2014 Turnagain Pass Avalanche Forecast

Mon, February 3rd, 2014

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Low (1)

Below Treeline
Below 1,000'

Low (1)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Low (1)
Below Treeline Below 1,000'		Low (1)

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

Deep Persistent Slabs

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

More info at Avalanche.org

The unusually warm and wet weather of late January has given way to a period of cooling. This gradual cooling has allowed the once saturated snowpack to “lock up” in many locations. The end result is a stout crust on the surface. This crust is now over 2 feet thick in places and can support a tremendous amount of weight. Because of this, it will be very difficult to trigger an avalanche in all but the highest elevations of the forecast zone.

In steep upper elevation starting zones above 3,000’, the possibility still remains for triggering a deep, dangerous slab. Weak snow near the ground still exists. This weak snow is now covered with slabs up to 6’ in depth. The likelihood of triggering one of these slabs is low today. However, if you were to trigger one of these slabs the end result would be a high volume avalanche that would be unsurvivable.

This is a difficult avalanche problem to assess. The easiest way to deal with this problem is to avoid steep terrain in the upper elevations. Avoiding steep rollovers & thin spots in the slab will also minimize the possibility of triggering a deep slab avalanche today.

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

It is also worth paying attention to old wind slabs that formed last week. These slabs exist in pockets in the higher elevations and will be on the shallow side, less that 10” in depth. Avoiding these pockets will help to minimize the greater hazard of losing control in steep terrain on a slick, hard crust. A fall in steep terrain today will be very difficult to arrest, hence the term “slide for life” conditions.

Weather

Mon, February 3rd, 2014

No precipitation has fallen over the past 6 days. Ridge top winds over the past 24 hours averaged 10mph out of the East with a gust to 32 mph. Temperatures at the Sunburst station at 3,812′ have averaged 25 F.

Today expect dry conditions with high clouds. Ridgetop winds will be in the 15-20mph range out of the SE and temperatures will be in the mid to high twenties F.

A large area of weak high pressure over much of the state will continue to dominate our weather through the week. A shift in the overall weather pattern looks to be on the distant horizon (next weekend). Stay tuned for timing and more details later this week.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/28/22	Turnagain	Avalanche: Turnagain Pass – late May wet slab cycle	CNFAIC Staff
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

Riding Areas

Updated Wed, June 01st, 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	Closed	Closed as of June 1st.
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.