JOPLIN, Mo. (KMOX) - Just a glimpse of the worst tornado damage in modern history “shocks you to the core.”

20-year-old Oliver Clark says, while disasters in Haiti, Japan and even New Orleans can seem remote, it’s hard to dismiss such hardship happening on the opposite end of the state.

Clark traded his front-row Cardinals tickets for a day working on the front-lines.

“They’re not letting anybody work more than three or four hours, because the work is so physically and emotionally draining,” he says. “I’m actually sitting in the shell of a home right now, and just looking around, you can’t imagine it until you’re actually here.”

He and other volunteers were told that if they saw an American flag flying in front of ruins, it meant that somebody died there in the storm.

“There are American flags up and down every street,” he says.

Listen / Clark, on clearing out the home of a victim:

Listen / Clark, on the desire of Joplin residents to move on: