Tue, March 18, 2014 Turnagain Pass Avalanche Forecast

Tue, March 18th, 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

Once again, the main concern boils down to how our snowpack is adjusting to last week’s 3-5′ of heavy storm snow. The good news is, all signs for the past couple days have pointed to the new snow/old snow interface (3-5′ slab over weak preexisting snow) gaining strength. Though this is great news, it’s not something to completely hang a hat on, yet. It was only 3 days ago now that we had good enough visibility for folks to test the slopes and come away with a handful of human triggered large – and dangerous – avalanches. Also, we are still only 4 days out from the end of the storm itself. A bit more time to really let the snowpack prove innocent is warranted.

Though the likelihood of triggering a deep slab continues to decrease, the size of a potential slide remains large. Due to the high consequences, conservative terrain choices remain the best way to manage the problem. This means avoiding steep slopes, especially those with prior wind loading, and likely trigger points. Likely trigger points include shallow spots in the snowpack and steep rollovers. For those with a higher risk tolerance, safe travel practices are key in avalanche terrain – this includes only exposing one person at time and keeping a close eye on your partners.

*Areas that have a higher likelihood are places that did not receive as much snowfall from last week’s storm and have a shallower overall snowpack. For example the central Kenai – Palmer Creek area, Silvertip region and Summit Lake zones.

Avalanche Problem 2

Dry Loose

Dry Loose

Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

More info at Avalanche.org

By the look of the satellite imagery this morning, the sun may shine more than expected today. Also, the winds are slated to be calm to very light. These factors combined can create significant warming at the snow surface. If this is the case today, watch for damp to wet loose avalanches on southerly aspects. These would likely just entrain the light 3-5″ of snow from Sunday.

Weather

Tue, March 18th, 2014

It was one of those overcast and low visibility days yesterday. Light snow showers were off and on but only added a trace of snow. Temperatures during the past 24-hours have averaged in the upper teens on the ridge tops and winds have been light, 5-10mph, from the East.

Today, we may see a few snowflakes before skies begin to clear. Temperatures are expected to climb to the low 30’sF at 1,000′ and around 20F on the ridgelines. Winds look to shift to the NW this morning and remain light, around 5mph, before picking up to the 20mph range late tonight.

Mostly clear skies and mild temperatures are on tap for Wednesday and Thursday as high pressure builds over mainland Alaska. This high looks to persist into the weekend.

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.