Detailed Accident Report

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Date: 2003-01-22
Submitted By: GNFAC; Gallatin National Forest Avalanch
Place: North side of Wolverine Peak
State: MT
Country: USA
Fatalities: 1
Summary: 1 snowmobiler caught, buried, and killed



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WOLVERINE PASS AVALANCHE FATALITY

22 January 2003

SYNOPSIS:

One snowmobiler was caught and killed in an avalanche that occurred on Wolverine Peak near Cooke City Montana. The avalanche released on a wind-loaded slope, with a northeast aspect. The slope angle, which averaged 34 degrees, increased to 42 degrees at the crown. The crown was 3 feet at its deepest point, and 250 feet in width. The avalanche ran approximately 450 vertical feet, with an a-angle of 27 degrees. US classification of the avalanche is SS-4-AS-O.

WEATHER:

8 inches of new snow fall in the two days prior to the avalanche with the majority of the snow (5 inches) falling the previous night. This new snow was accompanied by strong winds, which added to the load on the slope. Temperatures were seasonal with highs in the mid-twenties and lows in the teens.

AVALANCHE:

21-year-old Andrew Greicar of Pisek, North Dakota was riding with his partner, Jamie Bennington of Park River North Dakota, in the mountains north of Cooke City, Montana. At approximately 2:30 in the afternoon the two became separated near Wolverine Pass for a period of 5-10 minutes. Bennington followed a snowmobile track to the base of a small slope on the shoulder of Wolverine Peak where he found a fresh avalanche and part of Greicar?s snowmobile sticking out of the debris. He located Greicar?s buried position using an avalanche transceiver and then ? upon hearing other snowmobiles near by ? left a stick in the snow to make location and went for help. It is unclear if Bennington carried the additional rescue gear necessary to extricate his partner.

RESCUE:

The snowmobile that Bennington heard was that of Yellowstone National Park Ranger Chan, who was in the area testing a portable radio repeater. Chan immediately called out the Cooke City SAR Group. Three members of that organization responded and overtook Chan and Bennington as they made their way back to the accident site. The three SAR members, along with Bennington, proceeded to the avalanche and uncovered Greicar within one foot of where the stick marked his location. He was buried approximately 5 feet deep. Rescuers preformed CPR but the victim was not revived.

SNOWPACK:

The avalanche released on a layer of small grained, faceted, crystals that formed during the first two week of January. Other slopes in this area had formed surface hoar during the same period, and the combination of the two different weak layers had subsequently been buried by 20 inches of snow that fell between January 14 and 17. Wide spread natural avalanche activity occurred immediately after this storm on slopes where the surface hoar was present and a snowmobiler was injured in an avalanche on January 18th. The snow that fell during the period of January 21-22 triggered another round of natural avalanching on many slopes in the Wolverine Peak area. Stability tests, preformed on January 24th adjacent to the slope that avalanched, found the weak, faceted layer to be extremely sensitive.

If you have questions about this incident please feel free to call me at 406-587-6984 or email me at sschmidt@fs.fed.us.

Scott Schmidt

Avalanche Specialist

Gallatin National Forest Avalanche Center

25 January 2003

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REPORTS FROM THE GNFAC

1/25/03

COOKE CITY AVALANCHE INFORMATION

Yesterday, Scott and Doug visited the site where a snowmobiler died in an avalanche on Wednesday. The avalanche released on a east-northeast facing slope on Wolverine Peak, which is 5 miles northwest of Cooke City. The avalanche was about 300 feet wide and ran 450 vertical feet. Slope angles ranged from the low 30?s to 44 degrees at the crown fracture. The avalanche released on a thin layer of faceted crystals that probably formed about two weeks ago. This layer formed at the same time that surface hoar formed on many slopes in the Cooke City area. The slab that formed on top of this layer was 2 to 3 feet thick.

Scott will issue the next advisory tomorrow morning at 7:30 am. If you get out in the backcountry give us a call with your observations. You can leave a message at 587-6984 or e-mail your observations to us at gnfac@avalanche.org.

1/24/03

COOKE CITY AVALANCHE INFORMATION

On the afternoon of January 22, 2003, a snowmobiler died in an avalanche near Cooke City, Montana. The avalanche occurred on the north side of Wolverine Peak. Two men had been riding in the area. One rider stayed in a meadow, while his partner rode away. It was snowing at the time and visibility was poor. After several minutes, his partner hadn?t returned and the rider in the meadow rode up the slope to find his partner. He saw fresh avalanche debris and commenced a search with a rescue beacon. He located the area where his partner was buried. Using his hands and a stick he was unable to uncover his friend. He left a stick in the snow marking the buried person?s location and left the site to notify the local Search and Rescue Group. Rescuers reached the site and dug through 4 feet (1.2 m) of debris before recovering the body.

At this time not much is known about the avalanche. Scott and Doug are headed to Cooke City. More information about the avalanche will be in tomorrow?s advisory.