Detailed Accident Report
Submitted By: JHMR
Place: Paintbrush Area; Jackson Hole
Summary: 2 skiers caught, 1 buried and killed
Submitted By: Mike Rheam,
Ski Patrol Avalanche Hazard Reduction Leader/Avalanche Forecaster
Jackson Hole Mountain Resort
Place: Toilet Bowl Run (located between Paintbrush and Tower 3 Chute)
Jackson Hole Mountain Resort
Two skiers were caught and carried; one was deeply buried and quickly recovered but did not survive.
The area known as Toilet Bowl was opened for the first day this season the morning of December 27th at 9:36am. Avalanche reduction efforts, including explosive work , were performed on that route the morning of December 27th, as well as on the days preceding the event, including the 26th, 25th, 23rd, 22nd, 20th, and 19th. Prior to the 27th, a storm that deposited significant snowfall and brought strong winds kept the upper mountain closed on the 25th and 26th. Avalanche reduction work was still performed in the Toilet Bowl area as well as throughout the resort on both of those days. Avalanche reduction efforts throughout the resort on December 27th produced only surface sluffs. Just prior to the triggering of the avalanche in Toilet Bowl, skiers triggered small surface slides in the steep rocky areas of the Alta chutes and in Amphitheater Rocks, an area very near Toilet Bowl.
Accident and Rescue Summary:
At 1:25pm the slide initiated in the upper area of Toilet Bowl. This occurred while one skier was helping another skier get his skis back on after jumping off a rock ledge and landing near an avalanche reduction bomb crater in an area that had seen significant skier traffic since it had been opened. The slide carried both skiers, burying one under approximately seven to ten feet of snow while only slightly burying the other. The slide was witnessed by two ski patrol members and one ski area guide. A radio call was made to patrol dispatch that at least one person was buried and to send rescue personnel, dogs, and equipment. Once the slide stopped moving and the visibility returned, one of the patrolmen on scene quickly questioned the slightly buried skier and a search was initiated. The buried skier, who was wearing an avalanche transceiver, was found by a transceiver search and probing within two minutes of search initiation. He was buried under approximately seven feet of hard debris near his last seen point. With the aid of additional ski patrol personnel and several bystanders who were in the area, the victimís head was uncovered within eight minutes of the slide and he was found to be unresponsive. Resuscitation efforts commenced and he was transported off the mountain to the Teton Village Clinic. Additional rescue personnel performed a transceiver search on the rest of the path while two dogs searched the debris. Once the transceiver search was completed, 40-50 personnel immediately covered the slope either with four organized probe lines or by assisting the dog handlers with the few light indications they detected. At 3:00pm the site was cleared for a fresh dog to search the slope, and the rescue was terminated at 3:30.
The starting zone of this avalanche had a northeast aspect and an average slope angle of 40 degrees. The elevation of the crown was 8,860 feet above sea level. It descended approximately 330 vertical feet to an elevation of 8,530 feet. The length of the track was approximately 675 feet long and 135 feet wide at both the crown and the toe. The depth of the crown face varied from 2 to 6 feet, with an average of 3 feet. In most areas, the bed surface was a rain crust. Failure of the slope most likely occurred on faceted snow above this crust and below a subsequent rain crust. The avalanche, classified as HS-ASu-R3-D2.5-O, deposited debris to a depth of 5 to 10 feet. The victim was buried approximately 7 feet deep, 90 feet uphill of the toe.
Weather and Snowpack History:
In November 2008 there were two significant rain storms that created thick rain crusts up to an elevation of at least 10,500 feet. The first of these events occurred on November 13th, and the second occurred on November 29th. Weak layers of faceted snow developed above and below these slick crusts. During the first 21 days of December, 32 inches of snow with 2.9 inches of moisture fell at the mid mountain snow study plot (8,180 feet) at the Jackson Hole Mountain Resort. In the six days before this incident 42 inches of new snow with 2.9 inches of moisture fell at this plot. This scenario loaded a snowpack with persistent deep instabilities and initiated the beginning of a deep slab avalanche cycle in the backcountry and in the resort that began on December 22nd.
Only one inch of new snow fell in the 24 hours that preceded this incident. Avalanche hazard reduction routes were run at the resort on the morning of this incident with no significant results reported or observed. The general avalanche hazard in the backcountry was considerable on December 27th. There was only one avalanche that was reported to have released that day in the backcountry, which occurred the evening of the 26th on the west side of Teton Pass.
A swarm of earthquakes with a magnitude of less than 4.0 on the Richter Scale occurred on December 27th in Yellowstone National Park. There is no evidence that this seismic activity caused the failure of this or any other avalanches.