Detailed Accident Report

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Date: 1999-12-26
Submitted By: Doug Fesler & Jill Fredston AMSC
Place: Hatcher Pass, in the Talkeetna Mountains,50 miles north of Anchorage
State: AK
Country: USA
Fatalities: 1
Summary: 1 snowmobiler caught, buried, and killed

Skyscraper Mountain Avalanche Accident Report

Prepared by Doug Fesler and Jill Fredston

Alaska Mountain Safety Center, Inc.

January 3, 2000

Location: 1/3 mile NE of Hatcher Pass @ approximately 3,300 feet, on the south side of Skyscraper Mountain in the Talkeetna Mountains of Alaska

Accident Date: December 26, 1999

Synopsis: On December 26, at 11:30 a.m., 37 year old Robert Keith Coyne was killed by a avalanche on Skyscraper Mountain near Hatcher Pass in the Talkeetna Mountains, Alaska while snowmobileing.

Report: The self-triggered avalanche occurred after Coyne's snowmachine became stuck while he was highmarking. Coyne was riding alone though the avalanche was witnessed by many others. At least six snowmachiners who were waiting their turn to highmark at the base of the slope escaped the slide by outrunning it on their machines. Witnesses reported that after Coyne became stuck and climbed off his machine, a small slide broke out below him. He was standing to the left of his machine (which was facing uphill), hanging onto the handlebars. The initial shear failure must have propagated upslope for within roughly 10 seconds, the slope several hundred feet above Coyne broke loose, carrying him and his machine downhill.

Approximately 20 people from the surrounding area began immediately searching for Coyne and at least one person rode to Hatcher Pass Lodge to request help. Because one or more of the first responders still had their beacons in the transmit mode, searchers unnecessarily dug several large holes in the debris. Searching continued for 2-3 hours before the perimeter of the slide was marked and the site cleared by Alaska State Park rangers due to continued hazard. During this time, a second slide released on a slope next to the searchers. Numerous other natural and human-triggered avalanches occurred during the next several hours, including a large natural release at 2:30 p.m. on Marmot Mountain which covered the uphill lane of the road with a foot of debris. By this time, law enforcement officers were asking an estimated 100-150 recreationists to clear the area in order to avoid further accidents and in hopes that unclaimed vehicles would help establish the number and identity of buried victims.

There were a number of major red lights flashing on this day:

? Terrain: The avalanche path consisted of a steep, tundra-covered bowl (estimated at 42? to 45?, 300' wide by 600' high) which funneled into a steep narrow neck (estimated 38? to 42?), with a bench and shallow depression (i.e., terrain trap) below it in the runout zone. A second larger bowl below the ridge was above the first. Coyne's highmark route was dead-center up the track of the path. He became stuck in the lower track (estimated at 75-100' above the runout zone).

? Snowpack: The area had received 3-6 feet of new and wind-loaded snow during the previous week on top of a relatively shallow layer of faceted snow that had been developing since early season (September). Widespread natural avalanche activity had been occurring in the area since the previous Wednesday on all aspects.

? Weather: Winds gusting over 75 mph were causing extensive snow redistribution and slab formation at the time of the accident. Snow-pluming along the ridges above the accident site and elsewhere could be clearly seen from the road. Lower elevation winds were cross-loading the accident site. Temperatures in the area had risen from near 0? the day before to 48? F at the time of the accident.

? Human: The victim was a local familiar with the area and skilled at operating his machine (Yamaha Mt. Max) in steep terrain, but along with others in the area, did not heed widespread clues indicating instability. He traveled alone, carried no avalanche rescue equipment, and had no known previous avalanche education. Because it was a holiday weekend, all three of the nearby parking lots were filled to capacity, despite the strong winds.

After the rescue attempt was called off on December 26th, a formal rescue was organized for the 27th, using the Motherlode Lodge as a staging area. Alaska Department of Transportation and Public Facilities artillery was used to test the stability of the snow and make the approach and accident site safe for rescuers. Approximately a dozen rounds of ammunition were fired, bringing down at least 2 slides, one of which covered the accident site (roughly 150' X 150') with an additional 4-8' of debris. Roughly 75 probers and 2 dog teams, transported by about 25 snowmachiners, searched the area all day in moderate snow accompanied by 35 mph winds. Three snowcats with blades were used to trench the area where debris depths exceeded 24 feet. Searchers then probed the trenches and side walls. Alaska State Troopers, Alaska State Parks, Alaska Search and Rescue Dogs, Alaska Search, Rescue, and Recovery Team, Nordic Ski Patrol, Mat-Su Motor Mushers, Glacier Snowcat, Alaska Mountain Rescue Group, Alaska Mountain Safety Center, the Red Cross, and numerous individuals, including Coyne's family and friends, participated in the search.

By 5:30 p.m. on 27 December, Coyne was located by probers. He had originally been buried under 7-8 feet of snow, with 4-6 feet of additional debris from the second slide. He was nearly midway in the runout zone on the east side. Coyne was found on his back, head downhill, diagonal to the fall line, with both arms stretched out in front of him, pointing towards the snow surface. His visor on his helmet was up. Coyne may have sustained mechanical injuries but this is unknown. He died instantly as indicated by his deep burial, lack of an air pocket, and the absence of an ice mask in front of his face.

Comments: In the United States, there has never been a documented live recovery when a backcountry traveler has been buried deeper than 7 feet because of the weight of the debris, the absence of surface clues, and the time it takes to remove the snow. It is worth noting that an avalanche beacon would not have changed the outcome of this accident. Search efforts for Coyne were hampered not only by deep debris deposits and near-blizzard conditions, but by the antagonistic actions of several family members. Three law enforcement officers responded to the scene as a precaution.

Historically, three others (miners) have been killed by avalanches on Skyscraper Peak and, more recently, two backcountry travelers (a snowboarder and skier) died in separate avalanche accidents in April Bowl across the valley.