During the Tsunami in 2005, some of my friends flew to Phuket in Thailand to lend hand to the Swedish search and then identification efforts, by working as interpreters. They said that many, many odd and frightening things happened (keep in mind that Swedish people do not believe in ghosts at all. It takes a lot to convince them).
Shadows would constantly move, weird noises like footsteps coming from behind, sounds of someone coughing and giggling and even sounds of people sitting around campfires. They claimed to have seen people appeared and disappeared in during the evening, even when there is still sun.
When they came back and told me these things, they are now afraid of the dark. And they now believe. I don’t know what to think about their stories, they could be bullshitting me but they appear changed when they came back.