Detailed Accident Report
Submitted By: Bob Kasun, Idaho Panhandle N.F.
Place: Selkirk Mountains west of Bonners Ferry
Summary: 1 snowmobiler caught buried and killed
On March 19, 2000, a snowmobiler was killed in an avalanche in the Selkirk Mountains west of Bonners Ferry, Idaho. A group of snowmobilers were in the Roman Nose Lake area, which is part of the Snow Creek Winter Recreation Area on the Idaho Panhandle National Forest. The victim was high marking a steep, wind loaded north facing slope when the avalanche occurred. As the victim was coming back down the slope, it fractured above him and carried him down through some trees and to the bottom of the deposition area. The party was equipped with transceivers and immediately began a beacon search for the victim. The victim was found approximately 13 minutes after the avalanche occurred. He was buried in three feet of snow. One of the party members called the Boundary County Sheriff's Office by cell phone. A deputy was dispatched and arrived at the accident scene within an hour. Efforts to revive the victim failed. It was determined that the victim died of trauma to the head as a result of hitting a tree as he was swept down the slope.
Type of avalanche was HS-AV-2-O. Depth of the crown fracture was from .5 to 2 feet and approximately 200 feet long. Slope at the starting zone was 45 degrees. Length of slide was approximately 600 feet with an average width from flank to flank of 150 feet. Depth of the deposition was approximately 5 feet. It was determined that the recently loaded wind slab released on two thin, dense unidentified layers. Although, after reviewing the snow crystals of the sliding surfaces at the crown, some facets were visible. Also, depth hoar was found in the area of the fracture point near a rock outcrop where the snow pack was shallower than the rest of the slide area.
Weather conditions at the time of the accident were unsettled and snowing with moderate southwesterly winds. It snowed heavily the day before the accident with southwesterly ridge top winds gusting 60 to 70 mph throughout the day. Avalanche conditions for the Selkirk Mountains were rated as considerable above 5000 feet with the suggestion that backcountry travelers avoid the steep and open north and east-facing wind loaded slopes.
Bob Kasun, Avalanche Forecaster
Idaho Panhandle National Forest