Every year, World Tsunami Awareness Day reminds us that early warning and education can save lives. Tsunamis, triggered mostly by undersea earthquakes, have caused some of the deadliest natural disasters in history, walls of water sweeping across coastlines with little warning, leaving behind destroyed lives, and lost generations.

The 2004 Indian Ocean Tsunami remains one of the most devastating examples. Striking on December 26, it killed more than 2,30,000 people across 14 countries, from Indonesia and Sri Lanka to India and Thailand.

Entire communities vanished in moments, and millions were displaced. Yet amid the destruction, stories of survival and courage emerged, one of the most inspiring being that of ten-year-old Tilly Smith from Surrey, England, who used her classroom learning to save thousands of lives.

“I was on the beautiful white sand beach of Mai Khao, in Phuket,” Tilly recalled in "Tilly Smith: In disasters, lessons save lives", a first-person account of her experience.

She wrote, “It was eight in the morning, and we were enjoying a family walk before breakfast along the beach.” Just the day before, she and her family, parents Colin and Penny, and seven-year-old sister Holly, had celebrated Christmas by the sea.

What happened next would turn her into a symbol of awareness and education. “I had watched a video before I went to Thailand,” she says, “and as soon as I got on the beach I recognized that the sea was not going in and out but was just coming in further and further. I also noticed there was a white froth on the surface of the sea — and I just had a gut feeling something was wrong.”

That intuition came from a geography lesson at Danes Hill School, Surrey. “My teacher, Mr. Karney, had shown us a video about earthquakes and tsunamis just two weeks before our holiday. We learned that an earthquake in the sea creates a tsunami. When I saw the sea behaving strangely, it clicked immediately.”

When her mother didn’t believe her at first, Tilly ran back to warn the hotel security guard, shouting that she thought there was going to be a tsunami, a word not known to many on the beach. Moments later, a message arrived confirming a tsunami had hit Indonesia and was heading their way.

“People overheard me, and when the guard confirmed it, everyone on the beach just ran,” she remembered. Her family and others rushed toward the hotel’s third floor. “From there you could see the waves coming in — it was manic. Everyone was grabbing their kids and running upstairs.”

Tilly’s quick thinking saved dozens of lives that morning. While devastation unfolded along the coasts of Asia, the beach where she stood was spared the worst, because people had time to flee. “My story appealed because it was one story that was positive out of all the devastation,” she later said. “As a 10-year-old, I knew about this disaster risk because I had learned about it at school.”

The experience left a lasting mark on her. “When we flew home, I remember security people asking on the plane who had lost family members — so many hands went up. That’s when the full reality sank in.”

Tilly would go on to become a global advocate for disaster risk education. Invited to Washington to meet then-UN Special Envoy, Bill Clinton.

She became a volunteer with the UN Office for Disaster Risk Reduction. “The big lesson for me from the Indian Ocean Tsunami,” she said, “is how important it is to educate children about natural hazards and disaster risk. Children can pass on what they learn at school to their parents and others in their communities.”

Post the incident, she continued to advocate that infrastructures such as schools themselves must be made safe from floods, quakes, and other disasters. “Thousands of schoolchildren have died in earthquakes in the last ten years,” she warned, recalling how children and youth successfully lobbied for safe schools, at the 2015 UN World Conference, in Sendai, Japan.

Why is it observed on November 5?

The United Nations General Assembly designated the date in December 2015, following a proposal by Japan, a country with a long history of devastating tsunamis, but also one of the most advanced in disaster risk reduction, and awareness education.

The date, November 5, has a special historical significance in Japan. It commemorates the story of “Inamura no Hi” (The Burning of the Rice Sheaves) from 1854.

A villager named Hiromura Hamaguchi had noticed the tide receding, a sign of an incoming tsunami. To warn his neighbours, he set fire to his harvested rice sheaves (“inamura”) on a hill, prompting villagers to run uphill to put out the flames. Moments later, a massive tsunami struck the coast, destroying the village but sparing those who had fled to higher ground.

Both stories depict the power of awareness, how it can save not just one, but thousands of lives during such adversities.