Skier triggered avalanche 3D Chute - Dream Mtn - Negatives

AVALANCHE OBSERVATION 3D Chute Drainage: June Lake
Submission Info josh feinberg Forecaster Tuesday, February 19, 2019 - 12:30pm

Red Flags:

Recent loading by new snow, wind, or rain

Avalanche Type:

Dry

Slab

Slope:

50degrees

Trigger type:

Skier

Crown Height:

3 ft

Aspect:

East

Weak Layer:

Storm Snow

Avalanche Width:

40ft.

Terrain:

Above Treeline

Elevation:

10 750ft.

Bed Surface:

Old Snow

Avalanche Length:

1 400ft.

Number of partial burials:

More detailed information about the avalanche:

An anonyous report of human triggered avalanche in 3D chute in the negatives area behind June Mtn that occured on Feb 19th around 12:30pm:

"A member of our 4 person party set-off and was caught in an avalanche yesterday in the San Joaquin/June/Negatives area, in what is popularly known as 3D chute. Others started slides in our runs as well in similar elevations. These fractures appeared to go down to the same rain/melt-freeze/ice layer. Very soft slab released, that left the entire chute with a barren exposed rain/ice crust.

These are my observations. I was at the drop-in with the skier/snowboarder who triggered the avalanche and I witnessed the break from above.

Weather: Sunny, light upslope wind, temp 10-20 degrees.

Snow: wind/storm deposited light powder

Aspect: East SE facing chute

Slope: 50-55 degree

Elevation: 10,750 ft

Avalanche size: R3*/D2*

2-3'+ crown/40' wide

1400' vertical slide

Skier/snowboarder triggered the slide about 20 feet down in his 2nd or 3rd turn. I witnessed snow moving to his periphery and above him as he was engulfed and then carried down the entire chute onto the bottom apron, about 1400 feet below. He was able to free himself from only partial burial and ride away with no major injury.

As a sidenote, It seemed possible that this chute slide naturally previously during the main storm event on this icy layer, and was filled back in with light wind deposited snow.

Avalanche Photos: