Detailed Accident Report
Submitted By: BTNFAC
Place: North Fork of Murphy Creek, Wyoming Range
Summary: 1 snowmobiler caught, buried, and killed
*** OFFICIAL REPORT FROM THE BRIDGER-TETON NF AVALANCHE CENTER ***
Photos of the accident site: www.jhavalanche.org
ACCIDENT AND RESCUE SUMMARY:
A snowmobiler from Montana was high marking a steep north to northeast facing bowl on the afternoon of Saturday February 6th when his sled became stuck. The avalanche occurred while he was trying to free his sled. The avalanche buried him 15 -20 feet down hill of his sled which was almost completely buried. He was buried approximately four feet under the surface. At the time of the slide two of his three companions were near the slide and the other one was across the bowl, completely out of the path. All three companions responded and performed a transceiver search, finding him in about ten minutes. They quickly uncovered him and were unable to revive. The victim’s body position and the rescuers level of training and medical efforts are unknown.
Star Valley Search and Rescue was called and arrived on scene that evening to transport the victim and assist the other party members.
The crown depth was 3-4 feet and propagated a distance of over 300 feet. The starting zone was between 40 and 45 degrees steep and faced to the north, with the crown propagating to include northeast and east aspects. The starting zone was rocky and devoid of vegetation. The avalanche ran a distance of over 1000’ and with the deepest debris in the upper third of the path with depths of over ten feet where the sled and victim were buried. The crown was not safely accessible. A pit near the flank showed 30 inches of consolidated, settled snow over two feet of well developed facets, crusts, and depth hoar.
WEATHER AND SNOWPACK HISTORY:
Early season snowfall followed by dry and cold periods created a base layer of well developed depth hoar, faceted snow and some crusts. This layering includes all the snow that fell through mid January. From January 19th through the accident date 45 inches of snowfall was recorded at the Blind Bull Summit Study Plot at 9000’. This partially settled snow rested on the faceted layers. Dry conditions on Friday and Saturday had resulted in inversion temperatures, with a high temperature of 27 degrees on Saturday adding additional stress to the unstable snowpack. The avalanche danger was posted as “Considerable” in the area at the time. The beginning of the advisory stated: “ A well developed, persistent weak layer of faceted snow lies at the base of the snowpack. In steep terrain, the potential continues for backcountry travelers to trigger deep hard-slab avalanches involving this layer. These dangerous hard slabs could be triggered by a single person, and more likely by heavier loads such as snowmobiles, even after a slope has been crossed multiple times.”
Additional information such as specific location and photos can be seen by going to jhavalanche.org and searching the event mapping page and by viewing the snowpack summery pages for the week of February 5th -11th.
*** MEDIA REPORT ***
From the Montana Standard: www.mtstandard.com
Avalanche kills Dillon snowmobiler in Wyoming
By the Billings Gazette staff - 02/08/2010
BILLINGS -- A Dillon snowmobiler was killed by an avalanche Saturday while riding in the Squaw Creek area in west-central Wyoming near Greys River.
Bob Joe Turney, 50, was killed after getting stuck while riding with three other snowmobilers, according to Lt. Brian Andrews with the Lincoln County Sheriff's Department. When Turney stepped off to free his machine, the 150-foot wide avalanche broke loose.
Avalanche danger at the time of the incident was rated considerable by the Bridger-Teton National Forest Avalanche Center. The avalanche occurred at about 9,000 feet elevation on a south-facing slope before 4:30 p.m., which was when sheriff's dispatch received a call.
Turney was wearing an avalanche beacon. His fellow snowmobilers located him within 10 to 15 minutes, Andrews said, and it took another 5 minutes to dig him out. The cause of death was compression asphyxiation, Andrews said.
Also in the Greys River area, another snowmobiler had a close call near Murphy Lake Road when he triggered an avalanche that buried him to his goggles, according to an avalanche center report. The snowmobiler deployed an avalanche airbag, a safety device meant to avoid burial in avalanches.
So far this winter, there have been 11 avalanche fatalities in the United States, five of them snowmobilers. This is the second avalanche death in Wyoming this winter. The first occurred on Jan. 6 when a Jackson Hole Mountain Resort ski patroller was swept off a cliff by an avalanche.
There have been two Montana fatalities caused by avalanches this winter, the first on Dec. 10 killed an ice climber in the Hyalite Canyon area near Bozeman and the second killed a Billings man on Jan. 3 who was snowmobiling near Cooke City.