Fri, April 05, 2013 Turnagain Pass Avalanche Forecast

Fri, April 5th, 2013

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

Moderate (2)

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

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

Wet Loose

Wet Loose

Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

More info at Avalanche.org

The wet avalanche problem was worse just a few days ago. At this point the cold freezing overnight is creating a stiff crust on the snow surface that takes time for the solar radiation to melt and penetrate into deeper layers. Roller balls and other signs of instability at the surface show up more quickly in powder snow than in our current crust. That being said, sunny skies and warm temperatures can be the trigger for avalanches this afternoon. Travel decisions should be adjusted accordingly to limit exposure to south facing slopes late in the day.

With freezing overnight, the temperatures in the deeper snowpack remain relatively cold. We are not yet reaching the isothermal status where larger and deeper avalanches are expected.

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

These are pictures of the Goat couloir avalanche from Tuesday, a great example of the worst case scenario right now. This appears to be a very large cornice failure, which triggered a slab below and to the side of the cornice. The resulting avalanche traveled far for this path.

Cornices will become less stable in the afternoon as the sun heats them up and weakens their overhanging structure.

Weather

Fri, April 5th, 2013

Several days of clear skies and strong temperature swings between day and night are creating a melt/freeze cycle on the snow surface. Temperatures last night dipped to the mid teens at 4000 feet elevation after reaching above freezing during the day. At sea level peak daytime temperatures hit the low 40s in some areas. Wind has been light, and we haven’t had any precipitation in several days.

Today’s weather looks like more of the same, but a change is expected tonight. Snowfall is in the forecast for the weekend and into next week.

Fitz will issue the next advisory Saturday, April 6th.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
01/31/23	Turnagain	Observation: Johnson Pass area	Megan Guinn / W Wagner Forecaster
01/29/23	Turnagain	Observation: Tincan Backdoor	AAS-Level 1 1/27-1/30
01/28/23	Turnagain	Observation: Sunburst	Brooke Edwards
01/28/23	Turnagain	Avalanche: Seattle Ridge	W Wagner
01/28/23	Turnagain	Observation: Tincan Common	Tony Naciuk
01/27/23	Turnagain	Observation: Sunburst	John Sykes
01/27/23	Turnagain	Avalanche: Lynx Creek	Megan Guinn / W Wagner
01/25/23	Turnagain	Observation: Cornbiscuit	John Sykes Forecaster
01/22/23	Turnagain	Avalanche: Tincan	Schauer/ Guinn
01/21/23	Turnagain	Avalanche: Seattle Ridge	Elias Holt

Riding Areas

Updated Fri, January 06th, 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	Open	Opened Dec 13th.
Placer River	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Skookum Drainage	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Turnagain Pass	Open	Opened Dec 13th.
Twentymile	Closed	Closed Jan 5th due to lack of snow (holiday storms rained away the snow at sea level).
Seward District
Carter Lake	Open	Opened Dec 13th.
Lost Lake Trail	Open	Opened Dec 13th.
Primrose Trail	Open	Opened Dec 13th.
Resurrection Pass Trail	Closed	Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor	Open	Opened Dec 13th.
South Fork Snow River Corridor	Open	Opened Dec 13th.
Summit Lake	Open	Opened Dec 13th.