Jackson Hole, Wyoming

From: The Snowy Torrents

Light snow continued to fall on December 1-2. At 0600 on December 2, the 24-hour snow stake showed 4 inches of new snow. Light snow was falling but late in the day the intensity increased. The ski area had not yet installed their wind instrumentation, but southwest winds during the day were estimated at 20 - 25 mph and caused some blowing snow. The high temperature reached 25ºF.

ACCIDENT SUMMARY
On Monday morning, December 2, Jackson Hole ski patrol members reported for their first day of work. The patrollers would be working on the mountain in preparation of the ski area's scheduled opening the following Saturday, December 7. Before heading onto the mountain, ski corporation avalanche forecaster Jim Kanzler gave a detailed briefing of the snow and avalanche conditions.

Most of the snowpack - structure information gathered by Kanzler was from a snowpit he had dug the day before on Teton Pass. There he found four weak shear planes. The easiest shear was 32 inches down from the surface where very weak faceted-snow grains covered an ice crust. Kanzler told the patrollers and avalanche control teams that he was most concerned about the deep-slab instability posed by this weak layer. Then patroller Peter MacKay related his experience with the same layer. A natural avalanche the week before on Teton Pass had destroyed a car: the avalanche released on the same ice crust layer. MacKay told the group that the layer was very weak, and that he was also concerned the layer could cause the deep-slab instability problems well into the ski season. Though deep - instability was the main topic of the morning's report, Kanzler also expressed concern for shallow surface slabs from instability in the new snows. After the morning meeting, avalanche control teams and work teams headed out onto the mountain.

At about 1000, three ski patrollers skied down from the top of the tram to Dean's Slide, high on the southeast side of Rendezvous peak. Near the top of the path a one-pound charge was tossed into a pillow of snow, but released no avalanche. The patrollers ski-checked the area by crisscrossing the slope one-at-a-time as they moved down to a lower shot placement. This time a two-pound charge was buried a little over 2 feet into the snow, but the result was the same: just a large hole blown into the snow. Again, skiing one-at-a-time the patrollers crisscrossed their way down the path. The trio experienced no signs of instability and continued on with the rest of their control mission.

Later in the morning kanzler rode the tram to the top of Rendezvous Peak (10,450 feet). He and John Carr headed to the north side of Rendezvous Bowl where Kanzler dug a pit. He was not happy with what he found. The pit showed deep-slab instability and very unstable conditions. The sliding layer was the same ice crust that he had found on Teton Pass, but in Rendezvous Bowl faceted-snow grains were both above and below the ice crust. At about noon Kanzler notified the two snow safety leaders by radio and advised them that the bowl should be closed. Rendezvous Bowl was quickly closed to all workers, even though the morning's control work with bombs and artillery on the entire mountain produced few avalanches and showed little evidence of instability. However, work crews could continue to work in areas adjacent to the bowl.

During the afternoon ski patrollers were busy stringing ropes and placing signs. At about 1600 a group of eight patrollers - on sign detail - left the top of Rendezvous Peak. It would be the last work project of the day; they spread out and started placing "closed" signs just below Corbett's Couloir on the eastern side of Rendezvous Bowl. The eight, Todd Harley, Margo Erjavec, John Huff, Bruce Tlougan, Jerry Balint, Glen Jaques, Jim Roscoe and Paul Driscoll, 48, regrouped on the Lower East Ridge traverse to look at Dean's Slide. It was about 16:15 hours. The morning's ski tracks had been mostly filled in by new snow and blowing snow, but only 5 minutes earlier three ski-area workers had just skied the upper portions of Dean's Slide. Balint suggested they ski down one - or two-at-a-time to place signs along the north side of the path.

Balint started down first with a shoulder load of signs. He made one turn and stopped to place a sign. Erjavec dropped in below and put in another sign. She was followed by the other patrollers who started to place signs. All of the patrollers but Driscoll were grouped together about 100 yards below the East Ridge traverse. Driscoll, with a shoulder load of closed signs mounted on 2 x 2 inch posts, had gone ahead of the others and was much lower on the slope when Jaques and Tlougan traversed out to make a turn. Tlougan watched a fracture suddenly zipper across the slope and instantly pull apart 4 -5 inches. He tried to self arrest by jamming his bundle of signs into the snow. At the moment it probably seemed like the thing to try, but within a second or two the whole slope fractured around him and started moving. He dropped the signs and started swimming motions and tried to steer himself toward some trees. The time was 1619. When the snow stopped he as caught on a small tree.

Jaques tossed his signs when he saw the slope fracture above him. The slide knocked him over and carried him a short distance. Balint was below Tlougan and off to the north side when the slide released. He heard Tlougan yell and turned around just in time to be clobbered by a wall of rushing snow. Tumbling in the flow, he was stripped of his skis and poles. He started swimming and fought to stay on the surface. When the moving snow stopped he too was only partly buried. Erjavec had just placed a sign and had her back to the slope when she heard some shouts. She glanced back to Tlougan, Balint and Jaques in the giant blocks of moving snow. She yelled out, "watch the workers," but before she could move she too was swept down by the slide. She was carried and partly buried a short distance down slope.

As soon as the snow stopped moving everyone was yelling for the person they has last seen. It took only a minute or two to account for everyone but Driscoll. Tlougan, Balint, Jaques and Erjavec were all okay and on the surface of the debris. But several minutes of yells and radio calls for Driscoll went unanswered.

Immediately they switched their beacons to receive and a beacon search was started. Someone called out on the radio and reported the avalanche.

RESCUE
Others on the mountain knew something terribly wrong had happened when they heard the radio calls for Driscoll. At the top of the mountain, patrol director Dean Moore and patrollers Bob Nelson and Mark Wolling were just leaving when they heard the first radio traffic. They waited for several minutes, but when they heard additional radio traffic asking about Driscoll they headed to the accident site. Moore's little group discussed getting rescue equipment, but when they heard another group would be at the Mountain Station (the top of the tram) within minutes, they rushed off. Moore stayed at the top of the slide to direct other patrollers to the debris via a route lower down the slope. He was fearful of unthinking rescuers crossing the remaining snow above the fracture line and triggering a second avalanche. Nelson and Wolling skied down to help.

Though the patrollers were experienced in the use of avalanche rescue beacons they had trouble picking up the signal. Several patrollers reported receiving a weak but false signal, and several others reported receiving the radio broadcast of the local FM station KMTN. This lead to some confusion and it was not until almost 10 minutes after the avalanche that Balint yelled out that he had a strong signal at the bottom of the debris. Immediately after the slide had stopped he had found his skis and started a beacon search working toward a bunch of signs scattered near the bottom of the debris.

Peter MacKay had a group of six patrollers working on the far side of Rendezvous Bowl when they heard the radio traffic about the avalanche. They immediately started walking uphill. Two patrollers continued up to Mountain Station to get a toboggan ready while the others climbed only high enough to safely traverse to the accident side. Only one patroller in the group had a shovel so he was instructed to wait at the top of the debris until Driscoll's position was pinpointed. At Mountain Station, Patrollers Ron Matous and Stuart Kennedy readied an akja (a type of rescue sled), but from the top of the mountain with their radio they could not talk to anyone at the accident site. Matous then heard over his radio that no one at Mountain Station was answering their radio. He raced inside and tried to use the phone to make a call about that last radio message but only got a busy signal. Minutes later he heard over the radio that they had found Driscoll, so he headed back outside. Before leaving the top, Kennedy asked if they should bring shovels or any other gear. Matous didn't think they needed more equipment so Kennedy set off with the akja. Matous followed on his skis. As he skied away he kept trying to reach the accident site rescuers over the radio but had no lick. He finally raised Moore who confirmed that no shovels, only the akja, was needed. It was only later, when he was almost to the debris, that Matous heard radio traffic requesting shovels.

The debris was quite frim, but moving over the large blocks of hard snow was difficult. Even so, the patrollers hurried to Balint's location. Once the beacon signal was pinpointed, ski-pole probes confirmed Driscoll's location. But there were not shovels. The patrollers started digging with the tails of their skis while the one patroller with a shovel skied down. It took 10 minutes of digging with the one shovel to reach Driscoll who had been buried 6 feet deep. More rescue equipment and shovels soon arrive, but it took an additional 20 minutes to uncover his body before rescuers could start CPR and move his body to the akja.

In hideous conditions Driscoll's fellow patrollers started the somber, but urgent evacuation. To describe the evacuation as difficult is an understatement. Darkness and moderate snow blinded the rescuers as they hauled the heavily-loaded akja in the deep snow. The patrollers had to break trail through the deep snow all the way to mid mountain before they could travel on packed snow. They reached the bottom of the mountain at 1823 where attempts by doctors to revive Driscoll were unsuccessful.

Buried for 40 minutes under 6 feet of snow was too long for Driscoll. The avalanche had pushed him - back first - against a tree. That blow probably took away what little breath he had when the snow stopped. The cause of death was suffocation.

AVALANCHE DATA
The avalanche that released under the patrollers was a large hard slab. The fracture line was 5 - 7 feet deep and extended 3200 feet across the slop. It was classified as an HS-AS-4, and it most likely released on the buried ice crust. Little data about the avalanche is known. Heavy snow that evening buried the avalanche site under a new blanket of deep snow.

A few days later, 21 kilograms of explosives were lowered into Rendezvous Bowl. The resulting avalanche released the entire bowl - over 2,500 feet across. It released on the ice crust but quickly stepped to the ground and traveled over 1,200 feet down the mountain.

COMMENTS
Dean's Slide, located about 400 feet below the top of Rendezvous Peak and on the east side of Rendezvous Bowl, is considered the safest way off the top of the mountain. Scattered conifers separate the path from the bowl, but early in the season the trees act like snow fences catching the blowing snow off Rendezvous Bowl. Long-time patrollers could remember only a few similar large slides from Dean's Slide, and most occurred early in the season.

The avalanche was not a post-control release even though explosives had been used on the path earlier that morning. Conditions changed dramatically during the day; new snow and winds added an additional 12 inches of new snow to the slope since the morning control work. This additional weight significantly changed the stability of the slope. A marginally stable slope that morning that resisted explosives became an unstable slope by late afternoon. The weight of eight patrollers was too much for a slope that only minutes before had supported the weight of three skiers.

Besides the changing snow conditions there were human factors that might have contributed to the accident. It was the patrol's first day on the mountain and little knowledge of the snow and stability conditions existed. Even though there was an obvious weak layer in the snowcover, the morning's control results with explosives were minimal. Since the explosives did not confirm the instability of danger, the patrollers may not have used as much caution as was necessary for being out on steep slopes so early in the season. Working in a ski area they may have been lulled into a feeling of security, but in reality they were dealing with backcountry snow conditions and the uncertainty of a backcountry snowpack.

The ski patrollers also learned a very painful lesson: an avalanche rescue beacon is worthless without a shovel. Before the accident the patrollers usually carried their shovels only during avalanche control missions done in the morning. Once the control work was finished, the shovels were then left behind. Now, when beacons are worn, the patrollers also carry shovels. Unfortunately this potentially deadly operating procedure - no shovel - continues to be practiced by many ski patrollers around the United States who wear avalanche rescue beacons.

What about the avalanche rescue beacons receiving the local FM radio station's broadcast? The transmitter for KMTN (96.9 MHz) is located above the town of Jackson, about 7 air miles away. An avalanche u beacon is not a radio (they work on the principle of audio induction), but the simple electronics of low frequency avalanche rescue beacons (2.275 KHz) can mix frequencies. In the presence of a powerful transmitter an avalanche rescue beacon can become a radio receiver. After the accident the ski area's avalanche rescue plan was updated to include a provision for rescue leaders to request the assistance from the County Sheriff to temporarily suspend KMTN's broadcast if interference is significant.

The loss of a co-worker and friend was a terrible way to start a ski season. Paul Driscoll's dearth was the first avalanche fatality at the Jackson Hole Ski Area in 21 years of operation. But sadly it would not be their last that season. Three months later, avalanches would claim another patroller and destroy buildings on the mountain (see accidents 86-10 and 86-15)