When the Boy Scouts from Troop 104 arrived at the Little Sioux Scout Ranch in Iowa on Sunday, they expected challenges, but nothing like this.
In a furious moment, Boy Scouts Zach Jessen and Blake Walling came face-to-face with an unanticipated twister, which decimated the cabin where they and dozens of other scouts had been huddled.
"They saw a rotation in the clouds," Jessen recounted. "We all grabbed our stuff from one building. We went outside. The alarm went off. We woke up everybody. We got the people to the shelter just in time, just before the tornado hit."
Boy Scout Zach Jessen said he never imagined his training would come into play this suddenly and in this tragic turn of events.
"Lights went out, everybody started screaming, scoutmaster popped in and yelled, 'Get under the tables, get under the tables!'" Jessen said, replaying the horrific scene.
Jessen said he heard screaming amid the roar of wind and rain, along with the whir of rocks rushing past his head and smashing against the table where he crouched, his body shielding a fellow scout's head. As the cabin gave way, he felt bricks, rocks and wood hit his back, while other debris flew over him.
"At that point I was thinking, 'Oh god, here I come — just can I have one more shot at life?'" Jessen remembered thinking. "I saw some people not even moving, and I was thinking, 'Please don't be dead. Please don't be dead.'"
Jessen was in charge of a group of eight boys. One of the boys, Ben Petrzilka, 13, died, trapped under a chimney.
The tornado took the lives of three other teenagers. They were identified as Aaron Eilerts, 14, from Eagle Grove, Iowa; and Josh Fennen, 13, and Sam Thomsen, 13, of Omaha.
When things grew still, Walling said he was scared, but his primary reaction was one of disbelief.
"I stand up and I look around and I see there's no tents around, there's trees in half, and you can still hear trees snapping over," Walling recalled, still a bit numb. "I couldn't really believe that all of this was actually happening, you know."
As Walling scanned the scene, he noticed the injured and dead were everywhere, buried under rocks, bricks and trees. He noticed that his peers were bleeding from cuts on their arms and legs.
After about five seconds, he said, he jumped into action.
"I got up and started lifting stuff off of people," he recalled. "You could see people doing CPR on other kids, and I got up and started to move the bricks, and there were people panicking, so me and Zach helped them."
He and Jessen lifted rocks and bricks to rescue their half-buried fellow scouts, and used pieces of metal to wedge and lift debris that was too heavy or large to lift.
"I was thinking of all the first aid I had learned over the years, how to treat certain injuries. I saw one person who was halfway in, halfway out, so I went over there and started lifting debris up, my ankle was hurting, so I got someone else to help me," Jessen said.
Despite his ankle injury, Jessen said he "wasn't even focused on [himself]" because he "was focusing on the other people who were trapped."
At least 42 of the injured scouts remain hospitalized with injuries ranging from cuts and bruises to major head trauma, said Iowa public safety commissioner Gene Meyer.
On the other side of the camp, Alex Way and Scott Staver also were being tested.
Way saw the tornado touch down 50 to 75 feet away from where he sought cover, but what his eyes saw didn't register with his brain.
"I was just thinking I didn't believe, didn't think I would be in one of these situations at a Boy Scout camp," Way said.
Way, Staver and others in their group were unhurt, but fallen trees had left them stranded.
After breathing deeply himself to let the reality sink in, Way ran to help other boys.
"Because they teach us to help them deal with shock, and I just used that to help a few boys through it," Way said.
Staver also began to feel overwhelmed by the situation. "I was really getting scared, stomach started to feel weird, hoping it would all be over. [I] told myself to take deep breaths and to think it's over and done," Staver recalled.
He remembered that some of the boys shared his reaction. "I did see some boys that they were really scared and started to cry," he said.
The governors of Iowa and Nebraska have called these boys "heroes," but these four best friends have other things on their minds.
"I wish I could have saved the one boy in my group," Jessen said. "I was just like, God, help his family through this because I know it won't be easy for him."
JUNG HWA SONG contributed to this report.