Navy Petty Officer 2nd Class Tyler Burdick, a hospital corpsman with six days left in his deployment to Afghanistan's Helmand Province, was looking out the armored truck's front passenger-side window when the footprints, or what they call "disturbed earth," began to pass beneath his seat.
Burdick picked up his radio to alert the truck behind him, but before he could, his 40,000-pound MRAP was launched 20 feet in the air. He felt the seat lift against him until they crested, then a momentary sensation of weightlessness and a hard jerk back down into the blast's crater.
Next, impact. The dust turned everything black.
Burdick, 32, comes from an outdoorsy family and aspired to be a competitive snowboarder long before that July 2010 attack set him down that path again.
He became an instructor at Snowbird after high school and then a part-student, three-parts ski bum while attending the University of Utah, but by 25 he had failed to find any sense of purpose at lower altitudes. He chose to enlist.
Four months after his first assignment, he was sent to Fallujah, Iraq, where he spent eight months helping a community still reeling from 2004's Operation Phantom Fury.
A second Iraq deployment was canceled during 2009's drawdown, but combat was heating up in southern Afghanistan's Helmand Province, where the majority of the world's heroin is produced and the U.S. was hoping to bite the hand that feeds the Taliban and al-Qaida.
His battalion chief called in his corpsmen. Three medics had been injured and one killed fighting in Afghanistan. They needed volunteers.
"And I was the first one to raise my hand," Burdick said. "I was naively eager to prove myself. I knew that I had the ability to do it, and that's what I had trained for."
"Doc" tended to Marines as they surveyed the desert on long patrols. Firefights were few, but IEDs were a constant threat, Burdick says.
Three months in, the day before Burdick's battalion came home for Christmas, a Marine hopped out of a truck to relieve himself. He stepped on a mine and his life was over.
When Burdick was hit, the first thing he did was check his watch. 4:01 p.m. A medic has to know how long somebody's been hurt.
He could hardly see or breathe through the cloud of dust as he tried to assess the scene. The driver had been knocked out by the blast and fallen into Burdick's lap. Two Marines in the backseat were also unconscious.
With the front doors jammed, Burdick decided he'd drag the driver out through the back.
But he couldn't.
When he looked down at his legs, he realized that he had gotten the worst of it. His right tibia and fibula were crushed and poking through his skin. His boots were ripped in half. The muzzle of his M-16 was pointed downward and the IED had exploded through the armor in the floor of the truck and sheared off the final 2 inches of the barrel.
"As soon as I saw it, I was like, 'Oh man, this is bad,'" Burdick says. "My Marines are asking me, 'Doc, what do we do?'"
He directed them to splint his legs together and was evacuated by a helicopter shortly after as, he's told, a massive firefight began against more than 40 insurgents in ambush.
Losing your ability to move is probably not easy for anybody, but it was extremely trying for Tyler Burdick.
After a fasciotomy on his right leg and surgery to clean out dirt, soil and pieces of shrapnel, he was transported to Walter Reed National Military Medical Center in Bethesda, Md.
There, doctors gave him an option: Amputate, and lose your legs but benefit from cutting-edge prosthetics that will allow you to return to a relatively active lifestyle, or, salvage your limbs and undergo grueling physical therapy and surgeries with no guarantee that you'll be active again.
He opted to keep his legs.
When his older sister Amika first saw him, "He was spitting fire," she says. "He was just like usual. Just, 'Get me out of here,' and 'What do we do next?'"
But Burdick was a harrowing sight. The bottoms of his feet were black, and even though he was in better shape than many others on the floor, she could see that, behind the easy smiles, he was scared.
"He's always putting on his brave face," Amika says. "He's not a guy who allows much weakness to show."
Instead of inviting pity, Burdick identified a new goal. When he was trying to decide whether to amputate his legs, he came across the story of world-class adaptive snowboarder Amy Purdy.
"I saw her snowboarding on her two prosthetic feet, and as soon as I saw her do that, I knew that everything was going to be OK."
It wasn't OK as quickly as he'd hoped.
By October 2011, he was in agony walking with a cane. He asked a doctor to amputate, and when he was advised to first try a high-tech brace called an Intrepid Dynamic Exoskeletal Orthosis, or IDEO brace, he felt impatient.
But to his surprise, the brace was a revelation.
Instantly, he could walk without a cane. Within weeks he could jog, and by the end of six weeks, he could run.
His first day back on his old snowboard was frustrating, but he bought some cheap bindings he could "chop up" with the help of some old friends at Snowbird and adjust for his disability.
The next day he was barreling down double blacks.
"He's always been kind of a wild guy," says his younger brother, Tim, who says Tyler took frequent breaks but went full bore in-between. "He's got more broken bones than anybody I know."
Burdick still plays "what if" and wonders what he could have accomplished in the two years he's spent saving his legs (which he may yet lose anyway). He's developing arthritis in his ankles, held together by screws that bend and break with activity. The bottoms of his feet are no longer cushioned, so when he lands flat on a jump, he says, it feels like taking a fist and pounding it into concrete. And his legs will always require medical treatment.
"When I think about all of that, it's frustrating," he said. "How many surgeries am I going to have to through in my lifetime to keep these legs?"
Burdick was medically retired from the Navy on Memorial Day 2012 and moved back to Salt Lake City in December 2012.
Through the National Ability Center in Park City, he began racing boardercross, in which multiple boarders compete on the same course simultaneously.
He trains with Purdy and her organization, Adaptive Action Sports, in Copper Mountain, Colo., and she says he often speaks of her role in his recovery. "And I never get tired of it."
She can relate. When Purdy was told she had to amputate her legs after contracting bacterial meningitis at 19, she was shown a photo of a girl running on two prosthetic legs and thought, "OK, if she can run, I can snowboard."
Purdy says the vets she trains with adapt fast because they're generally athletic and "can take a beating."
Burdick crashed in all four races last season. In Tahoe, he broke his left wrist. In Copper Mountain, Colo., the following weekend, he went into a turn too fast he can shred upward of 40 mph and plowed into an icy berm, getting knocked out cold and waking up with a dislocated shoulder and two broken ribs.
But he took second at the first-ever U.S. Paralympics Snowboarding National Championships at Copper Mountain in April, and when it was announced in May that boardercross will become the first-ever Paralympic event for snowboarders, "it turned into a huge opportunity," he says.
Currently ranked eighth in the world, he hopes to rack up enough points on the World Cup circuit for a ticket to Sochi in February. Team Utah Canyons coach Todd Johnson a former Army infantryman himself says it's possible, but there are challenges.
For starters, Burdick is adjusting to a specialized racing board he bought in the spring. He's also still improving his ability to go over bumps and jumps without catching air and thus slowing down. Unlike some opponents, Burdick can't use either calf muscle and has to leverage his upper body to stay grounded. But Johnson thinks that it will click someday soon.
"He's got the size, he's got the skill and the mindset to be a dominating force," Johnson says. "Once it all comes together, look out."
Like many athletes on the U.S. Paralympic team, Burdick is raising money through the gofundme crowdfunding site.
He lives in a fifth-wheel trailer off his military pension and support from the Team Semper Fi nonprofit for disabled athletes, but his training schedule gives him little time for work and "he's always been too proud to accept any help," from his family, said his sister Amika. "He's not living it up."
After taking seventh in the World Cup opener last month in the Netherlands, he has four races in January two at Copper Mountain and then two at Big White in British Columbia to determine whether he goes for gold. He'll have more surgery next summer and may yet opt to amputate his legs, but Russia comes first.
"I see myself making it. I'm going to make it. That's my only focus right now."