Fri, March 04, 2016 Turnagain Pass Avalanche Forecast

Fri, March 4th, 2016

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

No Rating (0)

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

Glide Avalanches

Glide Avalanches

Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

More info at Avalanche.org

Glide avalanches continue to release and glide cracks are growing daily. An observer on Wednesday noted movement in the Cornbiscuit glide crack over the course of two ski runs. There was glide avalanche that was observed on south face of Manitoba yesterday that occured sometime between 12 pm-4pm. Glide avalanches are still totally unpredictable and travel underneath glide cracks should be avoided.

Recent glide avalanche in the Seattle Creek drainage. This was initially observed Wednesday afternoon and Wendy got a photo of it yesterday.

The Cornbiscuit glide crack is huge, growing and scary… It is worth checking out the other photos from the observation on Wednesday.

Photo: Kevan Dee

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

The cornices are impressive and hang over many slopes in the advisory area. There was a report of a snowmachine triggered cornice fall in Warmup Bowl on Wednesday that took the rider by surprise. They luckily did not go over with the falling chunks of snow. Cornices have the potential to be quite dangerous if you take ride with them or if they fall from above onto you. Avoid travel on top, watch for cornice cracks and limit exposure while traveling below. We are not ruling out the possibility of a large cornice fall triggering an avalanche on the slope below due the massive loading potential.

Snowmachine triggered cornice fall in Warmup Bowl on Wednesday.

Additional Concern

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

Today is a transitional day as we say goodbye to the sunshine and the clouds move in with the possibility of snow showers. Depending on the thickness of the cloud cover we may still see some surface warming of the snowpack. We have had no reports of human triggered avalanches in the past few days. There is still the possibility of triggering lingering wind slabs in steep leeward terrain, especially unsupported convex slopes. If you are out in the mountains it is worth checking out surface conditions, as these will be what the next wave of snow hopefully bonds to. Southerly slopes have a crust; there have been reports of small surface hoar formation in some areas and in protected areas loose snow is starting to facet. In addition there is a wide array of wind-affected snow at higher elevations and a delightful rain crust lower down.

Loose snow avalanches: Steep protected areas have loose snow that may be enough to push you off your feet if it gains enough force and mass as it travels down slope with you. Manage your sluff by moving out of its path before it hits you.

Surface conditions at Turnagain pass.

Weather

Fri, March 4th, 2016

Yesterday was clear and sunny. There were some patches of valley fog. Temperatures were in the mid 20Fs to upper 30Fs. The winds were light and easterly. Temperatures dropped into the high teens to mid 20Fs overnight.

Today will be mostly cloudy with a chance of snow in the morning, increasing in the afternoon. 0-3″ of snow is possible. East winds will be light and temperatures will be in the mid 20Fs to 30Fs.

Rain and snow showers are forecasted tonight and tomorrow. This pattern will continue through the weekend as a low in the Gulf spins a series of weather systems into the area.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	26	0	0	138
Summit Lake (1400′)	23	0	0	42
Alyeska Mid (1700′)	25	0	0	104

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	22	ENE	10	22
Seattle Ridge (2400′)	25	–	–	–

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.