Detailed Accident Report

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Date: 2006-01-05
Submitted By: GNFAC; Doug Chabot
Place: south end of Mt. Abundance
State: MT
Country: USA
Fatalities: 1
Summary: 5 snowmobilers triggered slide, 2 snowmobilers caught and buried, 1 killed

***OFFICIAL REPORT***

MT. ABUNDANCE AVALANCHE FATALITY: 5 Triggered, 2 Caught and Buried, 1 Killed

January 5, 2006

Written by: Doug Chabot, Director, Gallatin National Forest Avalanche Center

SYNOPSIS

On Thursday, January 5, 2006, five snowmobilers were riding up the south face of Mt. Abundance in the Beartooth Mountains of southwest Montana. This popular riding area is accessed from Cooke City and is on the border of the Beartooth-Absaroka Wilderness in Gallatin National Forest. They triggered the slope and three were able to safely ride out while the remaining two were caught and buried. One victim was quickly located underneath his sled with an avalanche transceiver, uninjured. The other victim was located less than 20 feet away with his boot sticking out of the snow. He was dug out by members of his party within 10 minutes, given CPR, but was not successfully resuscitated. The avalanche released on a southeast aspect (150 degrees) at 10,100 feet. The avalanche was two to three feet deep and ran 1,200 feet long, 800 feet vertical and 700 feet wide. The victim was found face down in the debris with his head proximately 2 feet from the snow surface. The slope angle at the crown averaged 37 degrees with the steepest pitch reaching 45 degrees. The alpha angle of the slide was 24 degrees. The US Classification of the slide is HS-AM-D3-R4-O.

WEATHER

Cooke City experienced snowfall on 15 of the past 17 days prior to this accident, totaling 6.6 inches of SWE for over 6 feet of new snow. This was measured at the Fisher Creek Snotel site which is located at 9,100 feet in the Fisher Creek drainage, approximately 6 miles southeast of the avalanche. Winds were predominantly out of the west to southwest at 15-30 mph during this period, although that is extrapolated from sites tens of miles away. The mountains around Cooke City are alpine and notoriously windy.

Thursday, January 5th was the first clear, sunny day since December 19th. Winds were light and temperatures that day had a maximum of 27F (-2.75C) and a minimum of 11F (-11.55C).

DETAILS

On Friday, January 6th, I arrived in Cooke City with Felicia Ennis, a field partner volunteer to investigate the slide. We talked with Larry McKee, Gallatin National Forest FPO and Deputy Coroner about the accident. In February 2002 a snowmobiler was killed on the exact slope, so I was familiar with its location. Unfortunately, I was unable to interview members of the party since they already left town, however Larry and other members of Cooke City SAR filled in important details.

A group of 5 snowmobilers arrived in Cooke City at daybreak on January 5th. They drove non-stop from Minnesota and were familiar with the area. They made their way over to the southeast face of Mt. Abundance, a popular slope to climb. All 5 of them started climbing the hill at the same time around noon. We do not know where they were when it was triggered. Three of the riders were able to get off the slope; however two got caught and buried. Everyone had avalanche transceivers and a shovel. We do not know the level of their avalanche education or riding experience. Nor do we know if they knew the avalanche danger was rated Considerable on all wind-loaded slopes steeper than 35 degrees.

The first person was located with a beacon underneath his sled which was visible on the snow surface. He was buried more by the sled than the snow. It was reported that once the sled was moved off him he was easily extricated, uninjured. The second person was found with a beacon approximately 20 feet away. As they approached the fine search area, they found a part of his boot sticking out of the snow. His head was downhill, face down and buried horizontally. He was under 2 feet of debris and was dug out within 10 minutes. CPR was administered for one hour, but the victim was never resuscitated.

SNOWPACK

The slope failed on a 5 cm thick layer of 1.5mm mixed facets of 1F- hardness. This layer was buried under 75 cm of 1F to P hardness wind slab and was sitting on an ice crust 30 cm off the ground. Although wind loaded with all the new snow since Dec 19th, this slope had a thin snowpack before the storm?much thinner than other areas. Snow depths in the flanks were almost 200 cm compared with 112 at the crown. This early season, high elevation, alpine slope had facet growth from sub zero weather in Nov and Dec.

If you have any questions you can contact me at 406-587-6984. I can also be reached via email at dchabot@fs.fed.us

Doug Chabot

January 11, 2006

**INITIAL REPORT from GALLATIN NATIONAL FOREST AVALANCHE CENTER**

AVALANCHE INCIDENT

Yesterday, a snowmobiler died in an avalanche near Cooke City, Montana. Five riders were highmarking about noon when the avalanche released on the south end of Mt. Abundance. All of the riders were carrying avalanche rescue gear. Three were able to ride out of the avalanche. One was caught but not buried or injured. The fifth member of the party was buried under 2 feet of debris. He was located and dug out within 10 minutes but efforts to resuscitate him were futile. Our sympathy goes to the friends, family and rescuers associated with this tragic event. Doug Chabot is going to Cooke City to investigate this incident. When he finishes his investigation a detailed report will be posted at www.mtavalanche.com

**MEDIA REPORTS**

Minnesota man dies in avalanche near Cooke City

Associated Press

COOKE CITY -- A 49-year-old Minnesota man died Thursday in an avalanche about five miles north of here.

Loren Samuelson of Big Lake, Minn., was snowmobiling with four friends just north of the Montana-Wyoming border, when the slide occurred, said Park County Coroner Al Jenkins.

Deputy Coroner Larry McKee said the group likely triggered the slide by climbing on a heavy load of snow. The snow wall was 10 to 15 feet high and ran for 230 yards down the mountainside.

Samuelson was buried and apparently suffocated despite the efforts of his friends, who followed a signal from a transmitter he was wearing and dug him out within 10 minutes, McKee said.

A second man suffered minor injuries.