Wed, April 03, 2013 Turnagain Pass Avalanche Forecast

Wed, April 3rd, 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

RECENT ACTIVITY

The most notable avalanche we saw yesterday was off Goat Mountain in the Girdwood valley. We believe a cornice failed due to daytime heating and triggered a slab beneath. This is a common occurrence in this place this time of year. The travel distance of the avalanche was impressive, and farther than I’ve personally seen that path slide.

With continued high daytime temperatures, wet avalanche activity in the afternoon remains the most likely problem to see today. There are numerous examples of this happening over the last few hot sunny days.

Heat induced avalanches are easy to avoid, especially when nighttime temperatures dip below freezing as they are currently. Sometime in the mid afternoon when the snow surface becomes soft or wet, it’s time to avoid south faces, including spending time beneath south faces.

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 cornice problem is really an extension of the heat problem. As the sun bakes the mountains and temperatures rise in the afternoon, unstable features like cornices lose strength and may fail spontaneously.

This problem can be especially dangerous if they trigger larger slabs on the slopes below, as happened on Goat Mountain yesterday.

ADDITIONAL CONCERNS

Even shady aspects have had some avalanche activity since the last major snowfall. Some of these can be attributed to wind slab over loose near-surface-facets. Yesterday we found a low elevation north aspect slab that failed on buried surface hoar in the Placer valley. Everything we’ve seen with this character is breaking at the recent storm snow interfaces ~12-24 inches deep. These are common enough that all steep lines should be treated with a degree of respect.

Weather

Wed, April 3rd, 2013

Yesterday the warm and sunny weather continued. Wind up high reached into the teens and 20s overnight. Overall the only weather factor contributing to avalanche danger was the sun and warm temperatures.

Scattered rain and snow showers are forecasted today with mostly cloudy skies. Temperatures are still expected to reach into the 40s at sea level in the afternoon. If the sun doesn’t shine today there will be less concern for wet avalanche activity on south faces. Wind should be light from the southeast.

Graham will issue the next advisory on Thursday, April 4th.

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.