Avalanche: Sound of Music 3/8/2011

Observer Name:

Bruce Tremper, Jake Hutchinson, Jeff Lonn

Observation Date:

03/09/2011

Occurrence Date:

03/08/2011

Occurrence Time:

3:00pm

Region:

Sound of Music
Park City Ridgeline
Salt Lake

Location Name:

Sound of Music - Park City Ridgeline - backcountry area near Canyons Resort

Location

40° 41' 2.7168" N, 111° 35' 59.6184" W

Avalanche Characteristics

Elevation:

9100'

Aspect:

East

Slope Angle:

Trigger:

Skier

Trigger: additional info:

Unintentionally Triggered

Avalanche Type:

Soft Slab

Weak Layer:

Surface Hoar

Depth (avg):

18"

Width:

300'

Vertical:

300'

People Involved

Caught:

Carried:

Accident & Rescue Info

Terrain Summary:

This is the investigation of an avalanche incident and there is a report by the victim on our website as well. This just shows the results of our investigation of the profile of the avalanche and general dimensions, etc.

Sound of Music is a backcountry area near the Canyons Resort and is along the Park City - Mill Creek ridge line. The slope is around 9,100' and east facing. The trigger point was 40 degrees and most of the path is around 35 degrees. The skier who triggered the avalanche was skiing alone and rode the slide about 200 vertical feet and came to rest partially buried by the debris. There were no injuries.

The light was flat, but you can barely make out the fracture lines on the looker's right side of the path and the fracture propagated into three different terrain features.

Terrain Photos:

Weather & Avalanche History:

This was the first day following a large snow storm in which about 2 feet of snow fell with a lot of wind.

General Comments

We dug several profiles along the crown of the avalanche and found that it was new snow only. The wind had drifted snow onto this slopes, so it was a wind slab. But it broke out much wider and propagated much farther than the typical wind slab, which made us suspicious that there was another kind of weak layer involved.

The slab was 1.5 feet and broke out 300' wide and propagated to 3 different paths.

The slab slid on a thin, sun crust and we could find patches of surface hoar as the weak layer. The surface hoar was very small and very pockety. It probably formed in 1-2 days during the clear period before the storm.

Video 1:

General Comments 2

Canyons ski patrollers, Jake Hutchinson and Jeff Lonn looking at the fracture line. The total fracture was about 300' wide and took out three different paths.

General Comments 3

Looking down the path from the place where the skier came to a stop. The avalanche traveled much farther.

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