Tue, March 31, 2015 Turnagain Pass Avalanche Forecast

Tue, March 31st, 2015

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Low (1)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Low (1)
Below Treeline Below 1,000'		No Rating (0)

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

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

After five days of warm stormy weather deposited several feet of good ol’ Chugach Toothpaste at the upper elevations, we should see a break in cloud cover today. If this is the case, travel to the high elevations will be possible and with long days, long tours – winter is not over yet for some! We saw very little natural avalanche activity through this storm cycle. With the ‘sticky’ nature of the snow along with a lack of known persistent weak layers, the new snow is showing signs of stabilizing quickly. The human triggered avalanche activity that did occur was within the storm snow and relatively small.

All that said, it is springtime and that time of year where sunshine and daytime warming can be the main player for de-stabilizing the snowpack. Today’s concerns:

WET LOOSE AVALANCHES:
Steep slopes with a Southerly tilt, or lower elevations, in areas where the sun shines will have wet or damp loose snow avalanche potential. Expect these to occur naturally as well as be human triggered. Keep in mind, a wet or damp sluff can entrain a significant amount of snow in steep sustained terrain.

DRY LOOSE AVALANCHES:
Dry snow exists above 2,500′ and dry sluffs should be expected on shady Northerly slopes as well as Southerlies that have not yet been affected by the sun.

DRY SLAB AVALANCHES?:
All signs point to good bonding between the storm snow and the old underlying surfaces from last week. The one exception is upper elevation Northerly slopes. These areas may harbor faceted snow under several feet of storm snow and allow for the possibility of triggering a large slab avalanche. If you are headed to high elevation shady zones, above 3,500′ generally speaking, this is something to keep in mind and watch for.

Avalanche Problem 2

Cornice

Cornice

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.

More info at Avalanche.org

Cornices deserve a lot of respect right now. They have grown substantially during the past week and though some of these have fallen on their own, many are looming. Warm temperatures and solar gain can increase the likelihood for failure. Minimizing time spend underneath them as well as giving them a wide berth on ridgelines is extremely important.

Photo below: Natural cornice failure on the West Face of Pyramid – likely occurring Sunday 3/29. Note the storm slab avalanche most likely triggered by the falling cornice.

Weather

Tue, March 31st, 2015

It was another springtime day in the backcountry yesterday with temperatures warming at 2,000′ to the upper 30’s F. Cloud cover broke just enough for some visibility, yet it was in and out before clearing up in the evening. Ridgetop winds were in the 5-10mph range from the East before decreasing and switching to the North overnight.

Today instability showers will be over our area as we are in a break between storms. We may see up to 2″ of snow and light rain below 1,000′ in some areas and sunshine in others. Ridgetop winds will remain light from the North around 5-10mph and temperatures mild, upper 30’s F at 1,000′ and mid 20’s at 4,000′.

Wednesday night and into Thursday we will see one more weak low-pressure system move through before high pressure builds for the weekend. It could be a nice weekend for a supertour.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	33	0	0	59
Summit Lake (1400′)	32	0	0	10
Alyeska Mid (1700′)	34	trace	0.02	36

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	25	NE	6	22
Seattle Ridge (2400′)	28	n/a	7	23

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.