Detailed Accident Report
Submitted By: Jim Collinson, Snowbird Snow Safety Dept
Place: Mt. Baldy, Snowbird Ski Resort
Summary: 1 skier caught, buried, died later in the hospital
Location: Mt. Baldy separates the ski areas of Snowbird/Alta, rising to 11,068. The avalanche occurred on the northwest exposure at an elevation of 10,470.
History: This was the first day which the Mt. Baldy side of Snowbird was opened this season. Previous control work on the slope included: a 105 mm rifle bullet on November 20th, 2 lb. HE on December 9th, and two separate shots of 2 lb. HE on December 14th; one shot in the starting zone of the subsequent avalanche, the other shot on the lower flank of the subsequent avalanche, all with no results. All five of the Baldy routes were run on December 14th; these routes cover West Baldy, Northwest Baldy, and the western exposure of the Peruvian Ridge. 55 starting zones were tested with explosives or skis with no significant results. Access to Mt. Baldy was opened at 09:28. Prior to the avalanche, which occurred at 12:24, an estimated 300 people crossed the starting zone and or skied the slope that failed. A public cell phone call was placed to Ski Patrol dispatch while the slide was in motion.
Accident and Rescue Summary: At 12:24 a male snowboarder was on the high traverse of Northwest Mt. Baldy and initiated the avalanche; the crown face bisected the high traverse. The event occurred as he was crossing the slope but did not involve him. According to witness reports from near the starting zone, as the slide was in motion they spotted a person in the middle of the track who was hiking up the slope to retrieve a ski. Warnings were yelled, but when visibility returned, the slope was empty, the alarm was sounded to the ski patrol, and many public skiers and snowboarders in the area began a search for missing people. A hasty search team was immediately dispatched with dogs, beacons, and Recco. Probe teams were assembled and dispatched along with extra probes for the public on scene already searching. Due to approximately 150 people on site, their scattered equipment, and the resulting contamination of the deposition, the dogs had interest in numerous locations but were unable to locate the victim. The victim, a 27-year-old female, was the same person who had been seen hiking in the track. She was not equipped with a beacon or Recco and was located with a probe line at 58 minutes, 3 deep.
Avalanche Data: This slope has a northwest aspect, elevation of 10,470, and a slope angle of 36 degrees. The initial release was 1 deep, 35 wide, and 20 from crown face to stauchwall. As this pocket traveled down slope, it released the skiers left flank and reached a maximum width of 120. The average depth of the crown face was 1, with pockets of up to 3. As the avalanche descended, it gouged into old faceted snow and entrained much of the snow in the track. The avalanche ran 1,000 vertically, classified as HS-AR-R3-D2-O. The deposition had tongues that were up to 10 deep, averaged 5.
Weather and Snowpack History: After receiving a record amount of precipitation in the form of both rain and snow in early November, the Wasatch Mountains were under high pressure until the end of November building a very faceted snowpack. On November 28th a significant rime/rain event occurred to the highest peaks. Early December returned to high pressure and cold temperatures further deteriorating the snowpack above and below the rime event. December 8th broke the high pressure spell with a storm which deposited 1 of 6% snow. The night of December 12th had strong southwest winds; a finger/pencil slab was deposited. December 13th was the second storm of the month with 17 of 6% snow.
Danger Rating: The UAC rated the hazard at the upper end of moderate for this day. There had been no avalanches reported in the Cottonwood Canyons previously.