thanks you very mach
The following report was compiled by Matt Schonwald and is an initial investigation into the avalanche accident on Tuesday, February 27, 2006 that killed Aspen resident Jon Seigle and injured guide Gary Ashurst. The photographs were provided with permission by Bart of skipass.com.
Location of incident—Cime de la Plane, Montgenèvre, France off piste within area.
Number in party—3; 2 caught and 1 partially buried. Found by beacon within ~5 minutes. Party members were Gary Ashurst, Jon Seigle and Gary Sawyer
Type of activity—skiing
Preliminary Avalanche classification—SS-SR-R5-D3
Other avalanche information: Soft slab running 300 meters.
A non guided group of friends were skiing at Montgenèvre, a ski station on the Italian French border, 50 kilometers east of La Grave. At approximately 13:00 Gary A, Jon and Gary S started skiing down from the Cime de la Plane, an offpiste, north facing area between Montgenevre and Claviere.
With over a dozen tracks on the slope, they proceeded to a stand of trees at 2345 meters, left of the tracks on the slope. Gary A started down the right side of a small gully and pulled out to the right and stopped 100 meters down. Jon started down, skiing to the left of Gary’s track and after 30-40 meters, triggered an avalanche. Gary S observed the avalanche, the fracture occurring within 30 cm of the tip of his ski.
Gary S saw Gary A attempt to grab a tree before being swept up by the slab. Gary S lost sight of Jon within the first few seconds. Gary S responded once the avalanche stopped 300 meters down slope. He switched his transceiver to receive and proceeded down slope to the last seen point.
Approximately 50 meters below the last seen point, Gary S found Gary A’s ski and pack. At this point he heard Gary A calling out and proceeded down another 50 meters and found Gary A partially buried, with one foot and part of his face exposed.
A gendarme witnessed the slide and called it in to the PGHM immediately and the PGHM were on site about the time Gary S was digging Gary A out. The PGHM found Jon within another 2-3 minutes, above the snow, around a large tree about 30 meters to the left of Gary A’s position. Both victims were found over 200 meters down from the crown.
“We skied the top low angle pitch to the left of several fresh tracks.We traversed slightly to the left just below and to the side of the couloir. Gary A skied just right of center of the pitch and stopped on the flats on the right side out of the way. Jon skied next to the left of Gary A’s tracks.
After Jon had skied three or four turns the snow fractured just in front of my skis. Once the fracture occurred the slab started to accelerate very quickly. Jon continued to ski on the moving slab. Gary A saw the slab and tried to move out of the way and/or grab a tree. At this point both Jon and Gary were overtaken by the snow and disappeared.
After the slide stopped, I traversed to the right because of there was still a hunk of slab that had not released and almost no snow left in the couloir. I skied down to the right until I reached the shelf and then traversed back to where I had last seen Jon and Gary A then began the search. Getting no signal, I continued down the slide path through the trees and rocks. As I worked my way down I thought I heard a voice. Shortly after I spotted Gary A’s pack in a stand of small trees and a ski further down the hill.
At this point I heard the voice clearly. I responded and got a reply. As I moved down toward the sound of the voice I spotted Gary A’s boot sticking out of the snow in the middle of the next flats. As I was digging out Gary the helicopter arrived and located Jon’s body wrapped around a tree about 35 meters away.”
I performed a fracture profile, which suggested the failure layer to be surface hoar/near surface facets on a crust 10 cm above the ground. The slab was a meter thick with its deepest point at 137 cm. The trigger point was 30-40 meters down slope of the crown, with the slope angle of 26 degrees. The avalanche was approximately 150 meters wide and ran 300 meters.
In the picture below, the red line is the fracture. Gary Ashurst is the yellow sun and Jon Seigle is the purple star. The upper purple star is where the avalanche was triggered. The lower sun and star are the spots where Jon and Gary were found.
The report compiled by Matt Schonwald, he can be contacted through Mountain Madness
thanks you very mach