Sun, March 06, 2016 Turnagain Pass Avalanche Forecast

Sun, March 6th, 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

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

Welcome to spring! Even yesterday when skies were mostly covered with clouds the sun’s radiation still played a role in heating the surface of the snow. The sun’s warmth combined with already warm daytime temperatures has the potential to add stress to our avalanche concerns: wind slabs, loose snow, and cornice fall. Monitor the surface snow and plan your day accordingly.

Loose Snow: Yesterday’s new snow (5”) was not bonding well with the surface below and was easily triggered on steep test slopes. This new snow was fast moving and released easily from your ski tips. Keep this problem in mind if entering into terrain where falling could have high consequences. This avalanche problem can be managed by letting your ‘sluff’ move past you when descending. On solar aspect in the afternoon wet loose avalanches will be more difficult to manage and harder to escape. Look for natural point releases on steep slopes, near rocks, and consider avoiding aspects where the sun is heating the slope.

Wind Slabs: Yesterday this new snow arrived with moderate winds and just enough time has passed to help form cohesive slabs. It is unknown how well this new snow is bonding with the surface below, thus be on the lookout for wind slabs in the alpine. Pay attention for soft pillow shaped features, shooting cracks and ease into steeper terrain with caution.

Top 5″ of loose snow was easily triggered yesterday on steep test slopes in Turnagain Pass.

Avalanche Problem 2

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

Countless glide cracks continue to threaten large areas of terrain throughout Turnagain Pass, including a mine field of cracks that cover most of the Southwest face of Cornbiscuit. There were several glide cracks that slid on Friday in the Summit Lake area and one possible new glide avalanche in the Lynx creek drainage. Glide cracks have been widening and coming out of hiding after they were covered by wind and snow during the storm cycle that ended a week ago. Limiting time spent under cracks is crucial, as they will spontaneously release without warning.

One of several many large glide cracks along Cornbiscuit’s Southwest face. Photo by Kevin Dee.

Additional Concern

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

Very large cornice features can be found along most ridgetops throughout Turnagain Pass. Some have large cracks and remain precariously perched in place. As is the general rule, give them lots of space, and limit time under them. Today warming temps and sun will be adding more stress and a snowmachine or person too close could tip the balance.

Some cornice features may have large cracks like this one that overhangs the SW aspecet of Magnum. Photo taken on 3-2-2016

Weather

Sun, March 6th, 2016

Yesterday snow and rain showers left 6 € of new snow in the Turnagain Pass area, 2 € happened before 7am yesterday. By late morning snow turned to rain along the highway and a brief period of sun appearted mid-day. Rain/snow line was around 1400′. Temperatures spiked in the high 30’s F at Center Ridge Weather Station and Easterly ridgetop winds were moderate become light in the afternoon and evening.

Overnight temps remained just above freezing along the road corridor (33F) and skies remained overcast. Winds were light with no new accumulation after midnight.

Today expect isolated rain and snow showers throughout the morning and afternoon becoming partly cloudy by early evening. Temperatures are expected to reach the mid-high 30’s F by mid-day with sun being an influence with thin cloud cover.

Tomorrow a similar pattern of rain and snow showers will continue to move through Southcentral, Alaska.

Today’s weather forecast for scattered showers can produce a ‘greenhouse effect’ where thin cloud cover can trap short wave radiation from the sun and easily heat up the surface of the snow.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	32	4	0.4	141
Summit Lake (1400′)	33	1	0.1	44
Alyeska Mid (1700′)	33	7	0.7	108

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	25	ENE	15	49
Seattle Ridge (2400′)	27	n/a	n/a	n/a

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.