Torrent from above

The Onion Basin avalanche

By Emily Wolfe Explore Big Sky Managing Editor

BIG SKY – When it snowed in late September and early October this year, many backcountry users knew it meant trouble.

The early snow clings to high elevation north-facing slopes, slowly drying out and creating a weak layer at the bottom of the season’s snowpack. More snow blanketed the hills after Thanksgiving, followed by a bitter cold spell in early December that weakened the snowpack further. Then it dumped.

Avalanches were reported throughout southwest Montana at the close of 2013, some more than 1,000 feet wide, and others on slopes barely steeper than 30 degrees.

A New Year’s Eve storm deposited another heavy load, this time in the form of mixed rain and snow, and Gallatin National Forest Avalanche Center forecaster Mark Staples issued an Avalanche Warning on Jan. 1 for the northern Gallatin Range, which is south of Bozeman and northeast of Big Sky. This was the second such warning for that region in 10 days.

“Very dangerous avalanche conditions exist,” Staples warned, rating the danger high on all slopes. “Travel in avalanche terrain is not recommended, and avalanche run-out zones should be avoided.”

The avalanche

On New Years Day, three men rode snowmobiles into the northern Gallatins, planning to spend all day in the mountains. The group started at 9:30 a.m. from the Portal Creek trailhead, seven miles north of Big Sky on U.S. 191.

They were Ken and Kenneth Gibson, father and son ages 46 and 19, and Kenneth’s friend Zachary Walker, also 19. Ken Gibson was an expert snowmobiler, familiar with the area and aware of avalanche hazards, according to Staples. The younger men were experienced riders, as well, and Walker had been out riding with the Gibsons a few times prior.

All three had avalanche beacons, probes and shovels, and were familiar with their use, and both Gibsons wore airbag backpacks. As the group traveled through the backcountry, they passed crown lines from recent large avalanches.

Just before 2 p.m., they rode into the north end of Onion Basin, a remote area south of 9,948-foot Eaglehead Mountain. Kenneth got his snowmobile stuck, but because he was in the back the other two didn’t realize they’d lost him.

Debris from a recent natural avalanche was visible on one of the steep, 500-foot slopes encircling the basin, and they kept what they thought was a safe distance from the slopes above, Ken riding up into a gentle meadow, and Walker continuing out across it.

Walker saw the avalanche out of the corner of his eye just before it hit.

“The snowmobile was swept out from underneath me,” Walker told EBS. “I can assume I bounced off a couple of the trees in the island where I stopped, because I have some good bruises and got folded in half a couple times.”

He came to a stop mostly buried, his head covered in compacted snow but one arm free. He could barely breathe.

“My first thought was to stay calm and try and save as much air as I could,” he said. “Then I realized that I couldn’t hear anything.”

Feeling tree branches clued Walker in to his position. Using his hands until he could reach the shovel in his pack, he dug himself out (The photo at right shows where Walker’s snowmobile was buried).

Shaking and cold, Walker could see Ken’s tracks first headed downhill, and then straight into the path of the avalanche. He thought he could make out Ken’s snowmobile near the toe of the debris, so he began a beacon search, working his way a few hundred feet down before picking up a signal.

After pinpointing Ken’s location in approximately 10 minutes, Walker assembled his probe and quickly struck Ken’s boot. Digging, he uncovered Ken buried on his side, his head 3-4 feet deep. Walker tried calling 911 but couldn’t get a call through. He began CPR and after a few minutes dragged Ken out of the hole to a more level surface.

In another 10-15 minutes, Kenneth appeared, having freed his snowmobile. The two hardly spoke as they did CPR for another half hour, Walker said. After 40 minutes, there was still no sign of a pulse.

Walker then tried to use his SPOT rescue device, but because it wasn’t activated no signal went through, he said.

“We both knew that we had to get out before it got dark on us, but it was pretty difficult for Kenneth,” Walker said, referring to the decision to leave Ken.

With one snowmobile destroyed and another buried in the avalanche debris, they rode the third machine two hours back to the trailhead. At 6:30 p.m., they reached 911 via the OnStar phone service in their car.
Search and rescue did not attempt to launch a recovery that night.

“If he’d been alive, we might have considered it,” said Gallatin County Sheriff Brian Gootkin, whose office commands search and rescue operations. “Between the avalanche danger and the darkness, it’s really difficult to put our rescuers at risk.”

The recovery

The following morning, the Gallatin County Search and Rescue team contracted helicopter pilot Mike Carisch to fly from Bozeman to Big Sky, where he picked up Big Sky SAR member Andy Dreisbach, as well as GNFAC forecasters Staples and Eric Knoff at the Big Sky SAR building, located just east of the Community Park.

Another five members of the SAR team were already in place near Golden Trout Lakes, having snowmobiled up Portal Creek; several more were staged lower in Portal Creek; a group of skiers stood by at the highway; and others still coordinated operations at the Big Sky base. In total, 20 volunteers were deployed.

Under calm, gray skies, the flight to Onion Basin took approximately 15 minutes. The helicopter circled for a few minutes while the team assessed the scene for further avalanche danger.

Carisch left Dreisbach, Knoff and Staples in a safe spot near the toe of the avalanche debris, and Knoff called in their GPS coordinates to dispatch. They spent just over two hours investigating the accident site and packaging Burton’s body for transport.

In the meantime, Carisch flew to Bozeman to pick up a long line and a cargo net, and then to the Big Sky SAR base, where he rigged the helicopter to lift Ken’s body out.

The helicopter returned to Onion Basin, loaded up and flew to meet the SAR team staged near the Portal Creek Trailhead. They loaded the body into a snowmobile litter here – to avoid news coverage of the recovery and having to close the highway – and then transported him to 191 to meet the coroner.

By 2 p.m., the pilot had de-rigged the long line and picked up the rescuers from Onion Basin.

The investigation

Breaking 1-3 feet deep and 400 feet wide, the avalanche started at 9,200 feet, just below the ridgeline, said Knoff, who skinned to the crown to investigate. From crown to toe, it ran 1,100 feet slope-distance and 500 vertical feet, with debris ranging from 5-8 feet deep. The average slope angle in the starting zone was 38 degrees.

“While we can’t say for sure they triggered the slide, all evidence indicates they did,” Staples wrote in a follow up report. “Without active wind loading or cornices that could break and fall, the odds of it being a naturally triggered avalanche are very low.”

Remote triggers like this demonstrate a very fragile snowpack, Staples said.

“They knew the danger was elevated, they had beacons and rescue gear. They were riding in the trees and thought they were playing it safe, but they were underneath the slope… In these conditions with this snowpack, you can trigger avalanches from below.”

Speaking with EBS, Staples compared the weak layer to dominoes supporting a heavier slab of snow, with the “dominoes” extending from the steeper terrain down into the flats. “To get an avalanche, all we need to do is tip one of those ‘dominoes,’ and then the rest fall over.”

The December weak layer is likely to persist for much of the season.

“When you zoom out to 30,000 feet up, the bar has been set pretty low this year in terms of stability,” Staples said. “We have some seasons that are generally a little more stable and some that are generally a little worse. This is one of the worst.”

Gallatin County Search and Rescue

Gibson’s was the first avalanche fatality of the winter in Gallatin County, and the second rescue operation of three for the county SAR team this season, as of EBS press time on Jan. 8.

A volunteer organization with 100-plus members, the team functions under the Gallatin County Sheriff’s Office and has teams based in Bozeman, Big Sky and West Yellowstone, plus a number of specialty divisions including alpine hasty team, swift water, helicopter and avalanche, with experts in each field.

“I would put the caliber of the people that volunteer here up against anybody in the world,” said Lt. Jason Jarrett, Search and Rescue Commander for the Sheriff’s Office. With an average of 100 calls a year, the team is as busy as any in the Northwest, he added. “Gallatin County is a very outdoor recreation-oriented county… We didn’t move here for the beaches.”

Two-thirds of the team’s responses are in fact for locals in trouble, according to Sheriff Brian Gootkin (pictured here, with Big Sky SAR members during the Onion Basin incident).

“The perception is that [the people we rescue are] almost always from out of state, that they don’t have proper gear or know what they’re doing, but in many cases it’s the opposite,” Gootkin said. “It’s people from here who do know what they’re doing, but take unnecessary chances.”

Whether two or 20 miles back, SAR operations require resources – money, people and time – and they put rescuers in danger.

With modern snowmobiles allowing access to remote areas, the dynamic has changed, said Big Sky SAR member Steve Johnson, referring also to snowmobile-accessed skiing and snowboarding. “Every time that performance window expands, it raises the bar of what we might have to cope with in terms of a rescue situation.”

But technology has also increased the safety margin for rescuers, said Dreisbach, one of the rescuers who flew into Onion Basin and a four-year member of the Big Sky team. By using the helicopter on this mission, for example, the team accomplished in short order what could have been a multi-day technical extraction.

Courage under pressure

Sheriff Gootkin spoke kindly of what the two young men accomplished in such a traumatic situation. “It’s pretty amazing what they were able to do,” Gootkin said.

Walker told GNFAC Director Doug Chabot he had practiced with his beacon and was familiar with its use, but hadn’t taken an avalanche class.

“What Zachary did – digging himself out, and then immediately finding and digging out Ken, was impressive,” Chabot said. “You don’t see that often. He was in a really bad situation, and he did everything right.”

Preparation was key, Walker said. “The only reason I knew exactly what to do was because we trained for it, so when you do it and know what to expect, you don’t really have to think, it’s just instinct.”

Remembering Ken Gibson

Burton Kenneth Gibson, known as Ken, was born Sept. 28, 1967, to Burt and Kathleen Gibson, in Lewistown. He graduated from Fergus High School in 1987, and went to Spokane for college, according to his obituary.

Ken returned to Bozeman to take over the Rainbow Motel, and in March 1992, he married Rochelle Krillenberger. They had two children, Kenneth Keltz Gibson and Blaike Burton Gibson.

“He was one of the best riders I’ve ever seen, and I’ve seen the best,” said Brad Grein, a friend who’d known Ken for 15 years. “He was an unbelievable dad, always spending time with his kids, a good son, a good father, a good friend.”

In lieu of flowers, memorials may be made to the Kenneth and Blaike Gibson Education Fund, and can be dropped off or sent to any First Interstate Bank Location.