Every bit of information can make a difference in a disaster. Just ask Tilly Smith.
In December 2004, the 10-year-old English schoolgirl was vacationing on the coast of Thailand with her parents and her younger sister Holly.
"It was like paradise -- white sand and blue turquoise sea," Tilly remembered.
On the morning of Dec. 26, the family went for a long walk on the beach. But Tilly, now 14, noticed something was very different about the ocean that day.
"The water was really, really frothy. It wasn't calm and it wasn't going in and then out," she said. "It was just coming in and in and in."
She remembered that everything she was seeing reminded her of a lesson on tsunamis she'd had at school just a few weeks before.
Tilly's mother Penny Smith remembered that her daughter began to get hysterical as she desperately tried to convince her parents to return to the hotel.
"She kept saying, 'It bubbles, the water bubbles.' That's what she kept saying to me like that -- and it goes round and round. 'It's the water,' she kept saying, 'It's the water,'" Smith said.
Tilly's parents ignored her, but she persisted. "There is gonna be a tsunami, listen to me," Tilly said she told her parents,
She finally convinced her father, Colin Smith, to turn back to their hotel, where he approached a security guard stationed on the beach.
"And I said, 'Look, you probably think I'm absolutely bonkers, but my daughter's completely convinced there's gonna be a tsunami,'" he said.
Thankfully, the security guard listened to Colin Smith and his daughter Tilly that day in Thailand and began warning visitors. As dozens of tourists began streaming toward the hotel, Colin Smith waved frantically at his wife to return.
They were moving just off the beach when the massive tsunami surged toward shore.
"And then the next thing I remember is, Penny running, screaming 'Get the kids!'" Colin Smith said. "And I looked round and the water was just coming out of the sea."
Everyone has a so-called "disaster personality" -- a personal way of reacting in a sudden crisis, such as the way Tilly handled the oncoming tsunami.
And while a few people behave heroically, the truth is that most of us will simply helplessly freeze. But all that can change if we've done one simple thing.
Amanda Ripley, author of the book "The Unthinkable: Who Survives When Disaster Strikes -- and Why" said all you need is a little knowledge.
"Everything you've given your brain before things go bad matters a great deal," she said. "It's just amazing how much better your brain can do with a little bit of information."
When the tsunami hit, Penny Smith was shocked at the wall of water coming from the ocean. "I ran. And then I thought I was gonna die. And that was probably the most frightened I've ever been in my life," she said.
The Smiths just made it onto the second floor of their hotel when the tsunami smashed into the building, crushing everything in its path. The family watched the devastation from a balcony.
The giant tsunami killed a quarter-million people around the world that day, 10,000 of them in Thailand. There were several injuries at the Smith's hotel, but not a single fatality, a miracle British tabloids credited to Tilly, whom they dubbed the "Angel of the Beach."
Colin Smith said he knows how blessed his family truly was.
"It was later when we sort of went through what happened we thought how lucky we were, 'cause if she hadn't told us, we would have just kept on walking," he said. "I'm convinced we would have died, absolutely convinced."
Tilly's fast thinking saved her entire family and many tourists that day. All it took was knowledge and then acting on that knowledge to turn a potentially deadly day into a heroic one.
Ripley said Tilly was a perfect example of what people are capable of in a disaster situation.
"This is a story that gives us a lot of hope," she said, "because if a 10-year-old girl can save people from a tsunami with basic information, then certainly we are all capable of that."
As for Tilly, she said she "was just so glad that we were all safe and together."
To find out what kind of a survivor you are, take the Survivor IQ test.